Methods and compositions for cns delivery of iduronate-2-sulfatase

ABSTRACT

The present invention provides, among other things, compositions and methods for CNS delivery of lysosomal enzymes for effective treatment of lysosomal storage diseases. In some embodiments, the present invention includes a stable formulation for direct CNS intrathecal administration comprising an iduronate-2-sulfatase (I2S) protein, salt, and a polysorbate surfactant for the treatment of Hunters Syndrome.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of prior application Ser. No. 13/974,457,filed Aug. 23, 2013, which is a continuation of prior application Ser.No. 13/168,966, filed Jun. 25, 2011 (now U.S. Pat. No. 8,545,837), whichclaims priority to United States Provisional Patent Applications Ser.No. 61/358,857 filed Jun. 25, 2010; 61/360,786, filed Jul. 1, 2010;61/387,862, filed Sep. 29, 2010; 61/435,710, filed Jan. 24, 2011;61/442,115, filed Feb. 11, 2011; 61/476,210, filed Apr. 15, 2011; and61/495,268 filed on Jun. 9, 2011; the entirety of each of which ishereby incorporated by reference.

SEQUENCE LISTING

In accordance with 37 C.F.R. § 1.52(e)(5), the present specificationmakes reference to a Sequence Listing (entitled“2006685-1278_Sequence_Listing”, which was created on Nov. 11, 2015 as a.txt file and is 9.7 kilobytes in size). The entire contents of theSequence Listing are incorporated herein by reference.

This application relates to US applications entitled “CNS Delivery ofTherapeutic Agents,” filed on even date; “Methods and Compositions forCNS Delivery of Heparan N-Sulfatase,” filed on even date; “Methods andCompositions for CNS Delivery of Arylsulfatase A,” filed on even date;“Methods and Compositions for CNS Delivery of (3-Galactocerebrosidase,”filed on even date; “Treatment of Sanfilippo Syndrome Type B,” filed oneven date; the entirety of each of which is hereby incorporated byreference.

BACKGROUND

Enzyme replacement therapy (ERT) involves the systemic administration ofnatural or recombinantly-derived proteins and/or enzymes to a subject.Approved therapies are typically administered to subjects intravenouslyand are generally effective in treating the somatic symptoms of theunderlying enzyme deficiency. As a result of the limited distribution ofthe intravenously administered protein and/or enzyme into the cells andtissues of the central nervous system (CNS), the treatment of diseaseshaving a CNS etiology has been especially challenging because theintravenously administered proteins and/or enzymes do not adequatelycross the blood-brain barrier (BBB).

The blood-brain barrier (BBB) is a structural system comprised ofendothelial cells that functions to protect the central nervous system(CNS) from deleterious substances in the blood stream, such as bacteria,macromolecules (e.g., proteins) and other hydrophilic molecules, bylimiting the diffusion of such substances across the BBB and into theunderlying cerebrospinal fluid (CSF) and CNS.

There are several ways of circumventing the BBB to enhance braindelivery of a therapeutic agent including direct intra-cranialinjection, transient permeabilization of the BBB, and modification ofthe active agent to alter tissue distribution. Direct injection of atherapeutic agent into brain tissue bypasses the vasculature completely,but suffers primarily from the risk of complications (infection, tissuedamage, immune responsive) incurred by intra-cranial injections and poordiffusion of the active agent from the site of administration. To date,direct administration of proteins into the brain substance has notachieved significant therapeutic effect due to diffusion barriers andthe limited volume of therapeutic that can be administered.Convection-assisted diffusion has been studied via catheters placed inthe brain parenchyma using slow, long-term infusions (Bobo, et al.,Proc. Natl. Acad. Sci. U.S.A 91, 2076-2080 (1994); Nguyen, et al. J.Neurosurg. 98, 584-590 (2003)), but no approved therapies currently usethis approach for long-term therapy. In addition, the placement ofintracerebral catheters is very invasive and less desirable as aclinical alternative.

Intrathecal (IT) injection, or the administration of proteins to thecerebrospinal fluid (CSF), has also been attempted but has not yetyielded therapeutic success. A major challenge in this treatment hasbeen the tendency of the active agent to bind the ependymal lining ofthe ventricle very tightly which prevented subsequent diffusion.Currently, there are no approved products for the treatment of braingenetic disease by administration directly to the CSF.

In fact, many have believed that the barrier to diffusion at the brain'ssurface, as well as the lack of effective and convenient deliverymethods, were too great an obstacle to achieve adequate therapeuticeffect in the brain for any disease.

Many lysosomal storage disorders affect the nervous system and thusdemonstrate unique challenges in treating these diseases withtraditional therapies. There is often a large build-up ofglycosaminoglycans (GAGs) in neurons and meninges of affectedindividuals, leading to various forms of CNS symptoms. To date, no CNSsymptoms resulting from a lysosomal disorder has successfully beentreated by any means available.

Thus, there remains a great need to effectively deliver therapeuticagents to the brain. More particularly, there is a great need for moreeffective delivery of active agents to the central nervous system forthe treatment of lysosomal storage disorders.

SUMMARY OF THE INVENTION

The present invention provides an effective and less invasive approachfor direct delivery of therapeutic agents to the central nervous system(CNS). The present invention is, in part, based on the unexpecteddiscovery that a replacement enzyme (e.g., iduronate-2-sulfatase (I2S))for a lysosomal storage disease (e.g., Hunters Syndrome) can be directlyintroduced into the cerebrospinal fluid (CSF) of a subject in need oftreatment at a high concentration (e.g., greater than about 3 mg/ml, 4mg/ml, 5 mg/ml, 10 mg/ml or more) such that the enzyme effectively andextensively diffuses across various surfaces and penetrates variousregions across the brain, including deep brain regions. Moresurprisingly, the present inventors have demonstrated that such highprotein concentration delivery can be achieved using simple saline orbuffer-based formulations and without inducing substantial adverseeffects, such as severe immune response, in the subject. Therefore, thepresent invention provides a highly efficient, clinically desirable andpatient-friendly approach for direct CNS delivery for the treatment ofvarious diseases and disorders that have CNS components, in particular,lysosomal storage diseases. The present invention represents asignificant advancement in the field of CNS targeting and enzymereplacement therapy.

As described in detail below, the present inventors have successfullydeveloped stable formulations for effective intrathecal (IT)administration of an iduronate-2-sulfatase (I2S) protein. It iscontemplated, however, that various stable formulations described hereinare generally suitable for CNS delivery of therapeutic agents, includingvarious other lysosomal enzymes. Indeed, stable formulations accordingto the present invention can be used for CNS delivery via varioustechniques and routes including, but not limited to, intraparenchymal,intracerebral, intravetricular cerebral (ICV), intrathecal (e.g.,IT-Lumbar, IT-cisterna magna) administrations and any other techniquesand routes for injection directly or indirectly to the CNS and/or CSF.

It is also contemplated that various stable formulations describedherein are generally suitable for CNS delivery of other therapeuticagents, such as therapeutic proteins including various replacementenzymes for lysosomal storage diseases. In some embodiments, areplacement enzyme can be a synthetic, recombinant, gene-activated ornatural enzyme.

In various embodiments, the present invention includes a stableformulation for direct CNS intrathecal administration comprising aniduronate-2-sulfatase (I2S) protein, salt, and a polysorbate surfactant.In some embodiments, the I2S protein is present at a concentrationranging from approximately 1-300 mg/ml (e.g., 1-250 mg/ml, 1-200 mg/ml,1-150 mg/ml, 1-100 mg/ml, or 1-50 mg/ml). In some embodiments, the I2Sprotein is present at or up to a concentration selected from 2 mg/ml, 3mg/ml, 4 mg/ml, 5 mg/ml, 10 mg/ml, 15 mg/ml, 20 mg/ml, 25 mg/ml, 30mg/ml, 35 mg/ml, 40 mg/ml, 45 mg/ml, 50 mg/ml, 60 mg/ml, 70 mg/ml, 80mg/ml, 90 mg/ml, 100 mg/ml, 150 mg/ml, 200 mg/ml, 250 mg/ml, or 300mg/ml.

In various embodiments, the present invention includes a stableformulation of any of the embodiments described herein, wherein the I2Sprotein comprises an amino acid sequence of SEQ ID NO:1. In someembodiments, the I2S protein comprises an amino acid sequence at least60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98% identical to SEQ ID NO:1.In some embodiments, the stable formulation of any of the embodimentsdescribed herein includes a salt. In some embodiments, the salt is NaCl.In some embodiments, the NaCl is present as a concentration ranging fromapproximately 0-300 mM (e.g., 0-250 mM, 0-200 mM, 0-150 mM, 0-100 mM,0-75 mM, 0-50 mM, or 0-30 mM). In some embodiments, the NaCl is presentat a concentration ranging from approximately 137-154 mM. In someembodiments, the NaCl is present at a concentration of approximately 154mM.

In various embodiments, the present invention includes a stableformulation of any of the embodiments described herein, wherein thepolysorbate surfactant is selected from the group consisting ofpolysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80 andcombination thereof. In some embodiments, the polysorbate surfactant ispolysorbate 20. In some embodiments, the polysorbate 20 is present at aconcentration ranging approximately 0-0.02%. In some embodiments, thepolysorbate 20 is present at a concentration of approximately 0.005%.

In various embodiments, the present invention includes a stableformulation of any of the embodiments described herein, wherein theformulation further comprises a buffering agent. In some embodiments,the buffering agent is selected from the group consisting of phosphate,acetate, histidine, succinate, Tris, and combinations thereof. In someembodiments, the buffering agent is phosphate. In some embodiments, thephosphate is present at a concentration no greater than 50 mM (e.g., nogreater than 45 mM, 40 mM, 35 mM, 30 mM, 25 mM, 20 mM, 15 mM, 10 mM, or5 mM). In some embodiments, the phosphate is present at a concentrationno greater than 20 mM. In various aspects the invention includes astable formulation of any of the embodiments described herein, whereinthe formulation has a pH of approximately 3-8 (e.g., approximately4-7.5, 5-8, 5-7.5, 5-6.5, 5-7.0, 5.5-8.0, 5.5-7.7, 5.5-6.5, 6-7.5, or6-7.0). In some embodiments, the formulation has a pH of approximately5.5-6.5 (e.g., 5.5, 6.0, 6.1, 6.2, 6.3, 6.4, or 6.5). In someembodiments, the formulation has a pH of approximately 6.0.

In various embodiments, the present invention includes stableformulations of any of the embodiments described herein, wherein theformulation is a liquid formulation. In various embodiments, the presentinvention includes stable formulation of any of the embodimentsdescribed herein, wherein the formulation is formulated as lyophilizeddry powder.

In some embodiments, the present invention includes a stable formulationfor intrathecal administration comprising an iduronate-2-sulfatase (I2S)protein at a concentration ranging from approximately 1-300 mg/ml, NaClat a concentration of approximately 154 mM, polysorbate 20 at aconcentration of approximately 0.005%, and a pH of approximately 6.0. Insome embodiments, the I2S protein is at a concentration of approximately10 mg/ml. In some embodiments, the I2S protein is at a concentration ofapproximately 30 mg/ml, 40 mg/ml, 50 mg/ml, 75 mg/ml, 100 mg/ml, 150mg/ml, 200 mg/ml, 250 mg/ml, or 300 mg/ml.

In various aspects, the present invention includes a containercomprising a single dosage form of a stable formulation in variousembodiments described herein. In some embodiments, the container isselected from an ampule, a vial, a bottle, a cartridge, a reservoir, alyo-ject, or a pre-filled syringe. In some embodiments, the container isa pre-filled syringe. In some embodiments, the pre-filled syringe isselected from borosilicate glass syringes with baked silicone coating,borosilicate glass syringes with sprayed silicone, or plastic resinsyringes without silicone. In some embodiments, the stable formulationis present in a volume of less than about 50 mL (e.g., less than about45 ml, 40 ml, 35 ml, 30 ml, 25 ml, 20 ml, 15 ml, 10 ml, 5 ml, 4 ml, 3ml, 2.5 ml, 2.0 ml, 1.5 ml, 1.0 ml, or 0.5 ml). In some embodiments, thestable formulation is present in a volume of less than about 3.0 mL.

In various aspects, the present invention includes methods of treatingHunters Syndrome including the step of administering intrathecally to asubject in need of treatment a formulation according to any of theembodiments described herein.

In some embodiments, the present invention includes a method of treatingHunters Syndrome including a step of administering intrathecally to asubject in need of treatment a formulation comprising aniduronate-2-sulfatase (I2S) protein at a concentration ranging fromapproximately 1-300 mg/ml, NaCl at a concentration of approximately 154mM, polysorbate 20 at a concentration of approximately 0.005%, and a pHof approximately 6.

In some embodiments, the intrathecal administration results in nosubstantial adverse effects (e.g., severe immune response) in thesubject. In some embodiments, the intrathecal administration results inno substantial adaptive T cell-mediated immune response in the subject.

In some embodiments, the intrathecal administration of the formulationresults in delivery of the I2S protein to various target tissues in thebrain, the spinal cord, and/or peripheral organs. In some embodiments,the intrathecal administration of the formulation results in delivery ofthe I2S protein to target brain tissues. In some embodiments, the braintarget tissues comprise white matter and/or neurons in the gray matter.In some embodiments, the I2S protein is delivered to neurons, glialcells, perivascular cells and/or meningeal cells. In some embodiments,the I2S protein is further delivered to the neurons in the spinal cord.

In some embodiments, the intrathecal administration of the formulationfurther results in systemic delivery of the I2S protein to peripheraltarget tissues. In some embodiments, the peripheral target tissues areselected from liver, kidney, spleen and/or heart.

In some embodiments, the intrathecal administration of the formulationresults in cellular lysosomal localization in brain target tissues,spinal cord neurons and/or peripheral target tissues. In someembodiments, the intrathecal administration of the formulation resultsin reduction of GAG storage in the brain target tissues, spinal cordneurons and/or peripheral target tissues. In some embodiments, the GAGstorage is reduced by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%,90%, 1-fold, 1.5-fold, or 2-fold as compared to a control (e.g., thepre-treatment GAG storage in the subject). In some embodiments, theintrathecal administration of the formulation results in reducedvacuolization in neurons (e.g., by at least 20%, 40%, 50%, 60%, 80%,90%, 1-fold, 1.5-fold, or 2-fold as compared to a control). In someembodiments, the neurons comprise Purkinje cells.

In some embodiments, the intrathecal administration of the formulationresults in increased I2S enzymatic activity in the brain target tissues,spinal cord neurons and/or peripheral target tissues. In someembodiments, the I2S enzymatic activity is increased by at least 1-fold,2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold or10-fold as compared to a control (e.g., the pre-treatment endogenousenzymatic activity in the subject). In some embodiments, the increasedI2S enzymatic activity is at least approximately 10 nmol/hr/mg, 20nmol/hr/mg, 40 nmol/hr/mg, 50 nmol/hr/mg, 60 nmol/hr/mg, 70 nmol/hr/mg,80 nmol/hr/mg, 90 nmol/hr/mg, 100 nmol/hr/mg, 150 nmol/hr/mg, 200nmol/hr/mg, 250 nmol/hr/mg, 300 nmol/hr/mg, 350 nmol/hr/mg, 400nmol/hr/mg, 450 nmol/hr/mg, 500 nmol/hr/mg, 550 nmol/hr/mg or 600nmol/hr/mg.

In some embodiments, the I2S enzymatic activity is increased in thelumbar region. In some embodiments, the increased I2S enzymatic activityin the lumbar region is at least approximately 2000 nmol/hr/mg, 3000nmol/hr/mg, 4000 nmol/hr/mg, 5000 nmol/hr/mg, 6000 nmol/hr/mg, 7000nmol/hr/mg, 8000 nmol/hr/mg, 9000 nmol/hr/mg, or 10,000 nmol/hr/mg.

In some embodiments, the intrathecal administration of the formulationresults in reduced intensity, severity, or frequency, or delayed onsetof at least one symptom or feature of the Hunters Syndrome. In someembodiments, the at least one symptom or feature of the Hunters Syndromeis cognitive impairment; white matter lesions; dilated perivascularspaces in the brain parenchyma, ganglia, corpus callosum, and/orbrainstem; atrophy; and/or ventriculomegaly.

In some embodiments, the intrathecal administration takes place onceevery two weeks. In some embodiments, the intrathecal administrationtakes place once every month. In some embodiments, the intrathecaladministration takes place once every two months. In some embodiments,the administration interval is twice per month. In some embodiments, theadministration interval is once every week. In some embodiments, theadministration interval is twice or several times per week. In someembodiments, the administration is continuous, such as through acontinuous perfusion pump. In some embodiments, the intrathecaladministration is used in conjunction with intravenous administration.In some embodiments, the intravenous administration is no more frequentthan once every week. In some embodiments, the intravenousadministration is no more frequent than once every two weeks. In someembodiments, the intravenous administration is no more frequent thanonce every month. In some embodiments, the intravenous administration isno more frequent than once every two months. In certain embodiments, theintravenous administration is more frequent than monthly administration,such as twice weekly, weekly, every other week, or twice monthly.

In some embodiments, intravenous and intrathecal administrations areperformed on the same day. In some embodiments, the intravenous andintrathecal administrations are not performed within a certain amount oftime of each other, such as not within at least 2 days, within at least3 days, within at least 4 days, within at least 5 days, within at least6 days, within at least 7 days, or within at least one week. In someembodiments, intravenous and intrathecal administrations are performedon an alternating schedule, such as alternating administrations weekly,every other week, twice monthly, or monthly. In some embodiments, anintrathecal administration replaces an intravenous administration in anadministration schedule, such as in a schedule of intravenousadministration weekly, every other week, twice monthly, or monthly,every third or fourth or fifth administration in that schedule can bereplaced with an intrathecal administration in place of an intravenousadministration.

In some embodiments, intravenous and intrathecal administrations areperformed sequentially, such as performing intravenous administrationsfirst (e.g., weekly, every other week, twice monthly, or monthly dosingfor two weeks, a month, two months, three months, four months, fivemonths, six months, a year or more) followed by IT administations (e.g,weekly, every other week, twice monthly, or monthly dosing for more thantwo weeks, a month, two months, three months, four months, five months,six months, a year or more). In some embodiments, intrathecaladministrations are performed first (e.g., weekly, every other week,twice monthly, monthly, once every two months, once every three monthsdosing for two weeks, a month, two months, three months, four months,five months, six months, a year or more) followed by intravenousadministations (e.g, weekly, every other week, twice monthly, or monthlydosing for more than two weeks, a month, two months, three months, fourmonths, five months, six months, a year or more).

In some embodiments, the intrathecal administration is used in absenceof intravenous administration.

In some embodiments, the intrathecal administration is used in absenceof concurrent immunosuppressive therapy.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are for illustration purposes only, not for limitation.

FIG. 1 is an exemplary illustration showing IT-delivered I2S detected inthe neurons (arrows) of the cerebral cortex (FIGS. 1A and 1B) and thecerebellar cortex (FIG. 1C) including I2S in a layer of meningeal cellscovering the surface of the brain (arrow heads) following intrathecalinjections of 3 doses of I2S. Staining of 12S IHC in 2 dose injectedbrains was weaker (photo not shown). No positive 12S staining wasobserved for any type of cells in the brain of vehicle control animals.40×.

FIGS. 2A, 2B, 2C, 2D, and 2E are exemplary illustrations showingreversal of pathology in the brain of I2S knock-out (IKO) mice afterintrathecal-lumbar I2S injection. H&E stained brain tissues showednumerous cellular storage vacuoles (arrows) in the vehicle controlanimals. Cellular vacuolation was reduced throughout the brain in both 2dose (photo not shown) and 3 dose injected mice. Marked reduction wasfound in the 3 dose injected ones. 40×.

FIG. 3 is an exemplary illustration showing immunohistochemical stainingof LAMP-1, where there is a marked reduction of lysosomal activity inthe brains after 2 doses (photo not shown) and 3 doses of I2S treatmentcompared with vehicle controlled mice. The reduction was characterizedby the decrease in the number of LAMP-1 positive cells and lighterstaining intensity in the regions throughout the brain. 40×.

FIG. 4 is an exemplary illustration showing morphometry results from acomparison of the mean LAMP-1 positive area among wild-type (WT),vehicle untreated and I2S (2 and 3 doses) mice in the cerebral cortex(Cortex), caudate nucleus (CP), thalamus (TH), white matter (WM) andcerebellum (CBL) confirmed that there were significant reductions in theLAMP-1 positive staining in all areas of the brain evaluated. Data arerepresented as the mean±s.d. # P<0.05; *P<0.01; **P<0.001.

FIG. 5 depicts exemplary electron micrographs of brain cells showedpathological improvements at the ultrastructural level. Neurons ofvehicle treated mice had lamellated inclusions, zebra body-likestructures, and vacuoles containing granular storage material (insert),which was reduced in I2S injected mice. Oligodendrocytes of vehicletreated mice showed large electron-lucent storage vacuoles (arrow) whileoligodendrocytes of I2S-injected mice had minimal vacuolation. Scalebar: in neurons, 2 μm; in oligodendrocytes, 500 nm.

FIG. 6 depicts exemplary immunohistochemistry results demonstrating I2Sdetected in sinusoidal cells of the liver following intrathecalinjections of 3 doses of 12S. 2S IHC staining in 2 dose injected liverswas weaker (photo not shown). No positive 12S staining in the liver ofvehicle controlled animals. 40×.

FIG. 7 depicts exemplary tissue from the liver. Severe cellularvacuolation and abnormally high lysosomal activity is revealed by H&Estaining and strong LAMP-1 immunostaining were found in vehiclecontrolled animals compared to WT ones. Marked reduction of cellularvacuolation and LAMP-1 immunostaining was found after interthecaltreatment with 3 and 2 (photo not shown) doses of I2S treatment. H&Estaining revealed intracytoplasmic vacuolization was almost completelydisappear with a nearly normal liver cell structure. H&E, 40×; LAMP-1,20×.

FIGS. 8A, 8B, 8C, 8D, 8E, and 8F illustrate exemplary data comparingaggregation by SEC-HPLC for saline and phosphate formulations (all with0.01% Polysorbate-20): 1 month at ≤−65° C. and 40° C.

FIGS. 9A, 9B, 9C, 9D, 9E, and 9F illustrate exemplary data comparingaggregation by SEC-HPLC method for saline and phosphate formulations(all with 0.01% Polysorbate-20): 6 month at ≤−65° C. and 25° C.

FIGS. 10A, 10B, 10C, 10D, 10E, and 10F illustrate exemplary datacomparing aggregation by SEC-HPLC method for saline and phosphateformulations (all with 0.01% Polysorbate-20): 24 months at ≤−65° C. and2 to 8° C.

FIGS. 11A, 11B, 11C, 11D, 11E, and 11F illustrate exemplary datacomparing charges by SAX-HPLC Method for saline and phosphateformulations (all with 0.01% Polysorbate-20): baseline versus 1 month at40° C.

FIGS. 12A, 12B, 12C, 12D, 12E, and 12F illustrate exemplary datacomparing charges by SAX-HPLC Method for saline and phosphateformulations (all with 0.01% Polysorbate-20): baseline versus 6 month at25° C.

FIGS. 13A, 13B, 13C, 13D, 13E, and 13F illustrate exemplary datacomparing charges by SAX-HPLC Method for Saline and PhosphateFormulations (all with 0.01% Polysorbate-20): baseline versus 24 monthat 2 to 8° C.

FIG. 14 illustrates exemplary data comparing SDS-PAGE, Coomassiestaining for saline and phosphate formulations (all with 0.01%Polysorbate-20) at baseline and 1 month @ 40° C.

FIGS. 15A and 15B illustrate exemplary data comparing SDS-PAGE,Coomassie staining for saline and phosphate formulations (all with 0.01%Polysorbate-20) at 6 months 25° C. and over 16 months at 2-8° C.

FIG. 16 depicts exemplary tissues showing cerebrum of a 3 mg treatmentgroup animal. Positive I2S staining in meningeal cells. 4×.

FIG. 17 depicts exemplary tissues showing cerebrum of a 30 mg treatmentgroup animal. Positive I2S staining in neurons and meningeal cels. 4×.

FIG. 18 depicts exemplary tissues showing cerebrum of 100 mg treatmentgroup animal. Positive I2S staining neurons and meningeal cells wasstronger than in 3 and 30 mg treated animals. 4×.

FIG. 19 depicts exemplary tissues showing cerebrum of a 150 mg treatmentgroup animal. A large population of neurons was 12S positive along withstrongly positive meningeal cells.

FIG. 20 depicts exemplary tissues showing I2S positive neurons and glialcells, along with meningeal cells, within layer I of the cerebrum in a30 mg treatment group animal. 40×.

FIG. 21 depicts exemplary tissues showing I2S positive neurons, glialcells, along with perivascular cells, within layer III of the cerebrumin a 30 mg treatment group animal. 40×.

FIG. 22 depicts exemplary tissues showing I2S positive neurons and glialcells within the layer VI of cerebrum adjacent to the white matter in a30 mg treatment group animal. 40×.

FIG. 23 depicts exemplary tissues showing strongly positive I2S stainingin the neurons (cerebrum) of a 150 mg treatment group animal. 100×.

FIG. 24 depicts exemplary tissue showing I2S immunostaining of thecervical spinal cord in a 150 mg treatment group. 4×.

FIG. 25 depicts exemplary tissue showing strong I2S immunostaining inthe lumbar spinal cord of a 150 mg treatment group animal. 4×.

FIG. 26 depicts exemplary tissue showing strongly positive I2Simmunostaining of meningial cells, glial cells, and epi/peri/endoneurium(connective cells) was found in the lumbar section of a 150 mg treatmentgroup animal. 40×.

FIG. 27 depicts that the neurons in the lumbar spinal cord of a 150 mgtreatment group animal were strongly I2S positive. 40×.

FIG. 28 depicts exemplary results from a liver from a 3 mg treatmentgroup animal. Only sinusoidal cells were I2S positive. 40×.

FIG. 29 depicts exemplary results from a liver from a 30 mg treatmentgroup animal. Sinusoidal cells and hepatocytes were I2S positive. 40×.

FIG. 30 depicts exemplary results from a liver from a 100 mg treatmentgroup animal. I2S immunostaining was much stronger in the sinusoidalcells and the hepatocytes. 40×.

FIG. 31 depicts exemplary results from a liver from a 150 mg treatmentgroup animal. Strongly positive I2S staining was identified insinusoidal cells and hepatocytes. 40×.

FIG. 32 depicts exemplary results from a heart from a 3 mg treatmentgroup animal. I2S immunostaining was negative. 40×.

FIG. 33 depicts exemplary results from a heart from a 30 mg treatmentgroup animal Interstitial cells were I2S positive. 40×.

FIG. 34 depicts exemplary results from a heart from a 100 mg treatmentgroup animal. Positive interstitial cell staining for I2S. 40×.

FIG. 35 depicts exemplary results from a heart from a 150 mg treatmentgroup animal. Strongly positive interstitial cell staining for I2S. 40×.

FIG. 36 depicts exemplary results from a kidney from a 3 mg treatmentgroup animal. I2S immunostaining was negative. 40×.

FIG. 37 depicts exemplary results from a kidney from a 30 mg treatmentgroup animal. Glomerular and interstitial cells were I2S positive.

FIG. 38 depicts exemplary results from a kidney from a 100 mg treatmentgroup animal. Increased glomerular and interstitial cell staining forI2S. 40×

FIG. 39 depicts exemplary results from a kidney from a 150 mg treatmentgroup animal. Positive I2S staining of proximal tubular, glomerular andinterstitial cells. 40×

FIG. 40 illustrates the results of immunohistochemistry (IHC) studiesevaluating the CNS tissues of cynomolgus monkeys administered weeklydoses of iduronate-2-sulfatase (I2S). As determined by (IHC), there waswidespread cellular deposition of I2S throughout the CNS. In the graymatter I2S was detected in the neurons of the cerebrum, cerebellum,brain stem, and spinal cord of all groups in a dose-dependent manner. Inthe surface gray matter of the higher dose groups, large numbers ofcerebral neurons were positive for I2S staining in the surface cortex(FIG. 40A). I2S was also detected in neurons in the thalamus (FIG. 40B),hippocampus (FIG. 40C), caudate nucleus (FIG. 40D) and spinal cord (FIG.40E). Meningial and perivascular cells were also I2S staining positive(FIG. 40F). The identified scale bars correspond to 25 μm.

FIG. 41 graphically compares the clearance of iduronate-2-sulfatase(I2S) in the cranial and spinal pools by plotting the amount of I2S insuch pools relative to the time following administration.

FIG. 42 illustrates the dose dependant gray matter deposition ofintrathecally-administered iduronate-2-sulfatase (I2S) to non-humanprimates over six months. The illustrated staining intensity correspondswith accumulation of iduronate-2-sulfatase in the thalamus. In thepresent FIG. 39, the nuclei are counterstained by DAPI and appear asblue and protein (I2S) appears as green.

FIG. 43 illustrates the dose dependant accumulation ofintrathecally-administered iduronate-2-sulfatase (I2S) to non-humanprimates following a single injection and following multiple injectionsover a six month period. The illustrated staining intensity correspondswith accumulation of I2S protein in the cerebral cortex.

FIGS. 44A and 44B demonstrate the cellular localization ofiduronate-2-sulfatase (I2S) throughout the cerebrum of the non-humanprimate. FIG. 44A illustrates the cross-sectional view of brain tissueextracted from the cerebrum of the non-human primate, while FIG. 44Billustrates that particular areas of the region corresponding to threeareas of white matter tissue (designated W1, W2 and W3), the whitematter near the ventricle (VW) and the surface gray matter (SG) tissuesof the section identified in FIG. 44A.

FIGS. 45A, 45B, 45C, and 45D illustrate neuronal and oligodendrocyteuptake and axonal association of intrathecally-administerediduronate-2-sulfatase (I2S) to non-human primates following monthlyinjections over a six month period. In particular, FIG. 45A, FIG. 45B,FIG. 45C and FIG. 45D are illustrative of a filament staining of thecerebrum tissues of the non-human primate intrathecally administerediduronate-2-sulfatase (I2S) and respectively correspond to the threeareas of the white matter (W1, W2 and W3) and the surface gray matter(SG) regions identified in FIG. 44B. FIG. 45A illustratesoligodendrocyte uptake of intrathecally-administered I2S in the whitematter (W1) tissues. FIG. 45B and FIG. 45C illustrate oligodendrocyteuptake and axonal association of the intrathecally-administered I2S inthe W2 and W3 white matter tissues respectively. FIG. 45D illustratesneuronal uptake of the intrathecally-administered I2S in the surfacegray matter (SG) tissues.

FIGS. 46A, 46B, 46C, and 46D illustrate the cellular identification ofiduronate-2-sulfatase in the white matter near the ventricle (VW) of anon-human primate. As depicted in the superimposed image (FIG. 46D), theiduronate-2-sulfatase is not associated with myelin (red) (FIG. 46B). Inthe present FIG. 46, the nuclei are counterstained by DAPI (FIG. 46C)Protein (I2S) appears in the top left box (FIG. 46A).

FIGS. 47A, 47B, 47C, 47D, 47E, 47F, 47G, and 47H illustrate staining inthe tissues of healthy Beagle dogs that were intracerebroventricularly(ICV) or intrathecally (IT) administered a single injection ofiduronate-2-sulfatase (I2S). As depicted in FIGS. 47A-47H, I2S waswidely distributed throughout the gray matter of both the IT and ICVgroups as determined by immunohistochemistry (IHC). FIGS. 47A and 47Billustrate that in the cerebral cortex, neurons were positive for I2S inall six neuronal layers, from the surface molecular layer to the deepinternal layer in both IT and ICV groups. FIGS. 47C and 47D illustratethat in the cerebellar cortex of the IT and ICV groups I2S was detectedin neurons, including Purkinje cells. Similarly, FIGS. 47E and 47Fillustrate that in both IT and ICV groups a large population of neuronsin the hippocampus were positive for I2S. Finally, images g and hdemonstrate that 12S-positive neurons were also found in the thalamusand caudate nucleus in the both the IT and ICV groups. In the presentFIG. 47, I2S staining is indicated with arrows.

FIG. 48 comparatively illustrates corpus callosum tissues ofiduronate-2-sulfatase knock-out (IKO) mice that were either untreated orwere administered I2S intrathecally (abbreviation V=vacuole). Asdepicted, the treated IKO mice exhibited a reduction of cellularvacuolation characteristic of certain lysosomal storage disorders in thecorpus callosum and fornix tissues of the I2S-treated IKO mouse.

FIGS. 49A and 49B illustrate a marked reduction in the presence oflysosomal associated membrane protein 1 (LAMP1), a lysosomal diseasepathological biomarker, in the surface cerebral cortex tissues of thetreated IKO mouse (FIG. 49A) relative to the untreated IKO control mouse(FIG. 49B) under both 20× and 40× magnification.

FIG. 50 depicts an exemplary intrathecal drug delivery device (IDDD).

FIG. 51 depicts an exemplary PORT-A-CATH low profile intrathecalimplantable access system.

FIG. 52 depicts an exemplary intrathecal drug delivery device (IDDD).

FIG. 53 depicts an exemplary intrathecal drug delivery device (IDDD),which allows for in-home administration for CNS enzyme replacementtherapy (ERT).

FIG. 54 illustrates exemplary effect of vacuolization after a singleintra-cerebral injection of idursulfase in neurons (Purkinje cells).

FIG. 55 illustrates exemplary I2S activity in the Brain by dose andregion.

FIG. 56 illustrates exemplary data of immunohistochemical localizationof idursulfase at different depths of the cerebral cortex.

FIG. 57 illustrates exemplary I2S activity in the spinal cord of monkeyfollowing intrathecal dosing with idursulfase.

FIG. 58 illustrates exemplary I2S activity in monkey liver, heart andkidney after intrathecal dosing with idursulfase.

FIG. 59 depicts an exemplary schematic for an escalation Hunter-IT trialprogram.

FIG. 60 illustrates exemplary measurements of I2S concentrations invarious sections of brain tissue after 30 mg dose. Different plotscorrespond to different times of measurement.

FIG. 61 illustrates exemplary measurements of I2S concentration afteradministration over time via various routes of administration forvarious product concentrations.

FIGS. 62A, 62B, and 62C are exemplary illustrations of PET imaging of¹²⁴I-labeled idursulfase-IT in cynomolgus monkeys at t=5 hours followingIV, IT-L, or ICV dosing.

FIG. 63 illustrates and exemplary diagram of an intrathecal drugdelivery device IDDD.

FIGS. 64A, 64B, and 64C depict various features of an IDDD both within asubject's body (FIG. 64A), displayed on a flat surface (FIG. 64B), andthe insertion point of the catheter tip (FIG. 64C).

DEFINITIONS

In order for the present invention to be more readily understood,certain terms are first defined below. Additional definitions for thefollowing terms and other terms are set forth throughout thespecification.

Approximately or about: As used herein, the term “approximately” or“about,” as applied to one or more values of interest, refers to a valuethat is similar to a stated reference value. In certain embodiments, theterm “approximately” or “about” refers to a range of values that fallwithin 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%,8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less in either direction (greaterthan or less than) of the stated reference value unless otherwise statedor otherwise evident from the context (except where such number wouldexceed 100% of a possible value).

Amelioration: As used herein, the term “amelioration” is meant theprevention, reduction or palliation of a state, or improvement of thestate of a subject. Amelioration includes, but does not require completerecovery or complete prevention of a disease condition. In someembodiments, amelioration includes increasing levels of relevant proteinor its activity that is deficient in relevant disease tissues.

Biologically active: As used herein, the phrase “biologically active”refers to a characteristic of any agent that has activity in abiological system, and particularly in an organism. For instance, anagent that, when administered to an organism, has a biological effect onthat organism, is considered to be biologically active. In particularembodiments, where a protein or polypeptide is biologically active, aportion of that protein or polypeptide that shares at least onebiological activity of the protein or polypeptide is typically referredto as a “biologically active” portion.

Bulking agent: As used herein, the term “bulking agent” refers to acompound which adds mass to the lyophilized mixture and contributes tothe physical structure of the lyophilized cake (e.g., facilitates theproduction of an essentially uniform lyophilized cake which maintains anopen pore structure). Exemplary bulking agents include mannitol,glycine, sodium chloride, hydroxyethyl starch, lactose, sucrose,trehalose, polyethylene glycol and dextran.

Cation-independent mannose-6-phosphate receptor (CI MPR): As usedherein, the term “cation-independent mannose-6-phosphate receptor(CI-MPR)” refers to a cellular receptor that binds mannose-6-phosphate(M6P) tags on acid hydrolase precursors in the Golgi apparatus that aredestined for transport to the lysosome. In addition tomannose-6-phosphates, the CI-MPR also binds other proteins includingIGF-II. The CI-MPR is also known as “M6P/IGF-II receptor,”“CI-MPR/IGF-II receptor,” “IGF-II receptor” or “IGF2 Receptor.” Theseterms and abbreviations thereof are used interchangeably herein.

Concurrent immunosuppressant therapy: As used herein, the term“concurrent immunosuppressant therapy” includes any immunosuppressanttherapy used as pre-treatment, preconditioning or in parallel to atreatment method.

Diluent: As used herein, the term “diluent” refers to a pharmaceuticallyacceptable (e.g., safe and non-toxic for administration to a human)diluting substance useful for the preparation of a reconstitutedformulation. Exemplary diluents include sterile water, bacteriostaticwater for injection (BWFI), a pH buffered solution (e.g.phosphate-buffered saline), sterile saline solution, Ringer's solutionor dextrose solution.

Dosage form: As used herein, the terms “dosage form” and “unit dosageform” refer to a physically discrete unit of a therapeutic protein forthe patient to be treated. Each unit contains a predetermined quantityof active material calculated to produce the desired therapeutic effect.It will be understood, however, that the total dosage of the compositionwill be decided by the attending physician within the scope of soundmedical judgment.

Enzyme replacement therapy (ERT): As used herein, the term “enzymereplacement therapy (ERT)” refers to any therapeutic strategy thatcorrects an enzyme deficiency by providing the missing enzyme. In someembodiments, the missing enzyme is provided by intrathecaladministration. In some embodiments, the missing enzyme is provided byinfusing into bloodsteam. Once administered, enzyme is taken up by cellsand transported to the lysosome, where the enzyme acts to eliminatematerial that has accumulated in the lysosomes due to the enzymedeficiency. Typically, for lysosomal enzyme replacement therapy to beeffective, the therapeutic enzyme is delivered to lysosomes in theappropriate cells in target tissues where the storage defect ismanifest.

Improve, increase, or reduce: As used herein, the terms “improve,”“increase” or “reduce,” or grammatical equivalents, indicate values thatare relative to a baseline measurement, such as a measurement in thesame individual prior to initiation of the treatment described herein,or a measurement in a control individual (or multiple controlindividuals) in the absence of the treatment described herein. A“control individual” is an individual afflicted with the same form oflysosomal storage disease as the individual being treated, who is aboutthe same age as the individual being treated (to ensure that the stagesof the disease in the treated individual and the control individual(s)are comparable).

Individual, subject, patient: As used herein, the terms “subject,”“individual” or “patient” refer to a human or a non-human mammaliansubject. The individual (also referred to as “patient” or “subject”)being treated is an individual (fetus, infant, child, adolescent, oradult human) suffering from a diseasE.

Intrathecal administration: As used herein, the term “intrathecaladministration” or “intrathecal injection” refers to an injection intothe spinal canal (intrathecal space surrounding the spinal cord).Various techniques may be used including, without limitation, lateralcerebroventricular injection through a burrhole or cisternal or lumbarpuncture or the like. In some embodiments, “intrathecal administration”or “intrathecal delivery” according to the present invention refers toIT administration or delivery via the lumbar area or region, i.e.,lumbar IT administration or delivery. As used herein, the term “lumbarregion” or “lumbar area” refers to the area between the third and fourthlumbar (lower back) vertebrae and, more inclusively, the L2-S1 region ofthe spine.

Linker: As used herein, the term “linker” refers to, in a fusionprotein, an amino acid sequence other than that appearing at aparticular position in the natural protein and is generally designed tobe flexible or to interpose a structure, such as an α-helix, between twoprotein moieties. A linker is also referred to as a spacer.

Lyoprotectant: As used herein, the term “lyoprotectant” refers to amolecule that prevents or reduces chemical and/or physical instabilityof a protein or other substance upon lyophilization and subsequentstorage. Exemplary lyoprotectants include sugars such as sucrose ortrehalose; an amino acid such as monosodium glutamate or histidine; amethylamine such as betaine; a lyotropic salt such as magnesium sulfate:a polyol such as trihydric or higher sugar alcohols, e.g. glycerin,erythritol, glycerol, arabitol, xylitol, sorbitol, and mannitol;propylene glycol; polyethylene glycol; Pluronics; and combinationsthereof. In some embodiments, a lyoprotectant is a non-reducing sugar,such as trehalose or sucrose.

Lysosomal enzyme: As used herein, the term “lysosomal enzyme” refers toany enzyme that is capable of reducing accumulated materials inmammalian lysosomes or that can rescue or ameliorate one or morelysosomal storage disease symptoms. Lysosomal enzymes suitable for theinvention include both wild-type or modified lysosomal enzymes and canbe produced using recombinant and synthetic methods or purified fromnature sources. Exemplary lysosomal enzymes are listed in Table 1.

Lysosomal enzyme deficiency: As used herein, “lysosomal enzymedeficiency” refers to a group of genetic disorders that result fromdeficiency in at least one of the enzymes that are required to breakmacromolecules (e.g., enzyme substartes) down to peptides, amino acids,monosaccharides, nucleic acids and fatty acids in lysosomes. As aresult, individuals suffering from lysosomal enzyme deficiencies haveaccumulated materials in various tissues (e.g., CNS, liver, spleen, gut,blood vessel walls and other organs).

Lysosomal Storage Disease: As used herein, the term “lysosomal storagedisease” refers to any disease resulting from the deficiency of one ormore lysosomal enzymes necessary for metabolizing naturalmacromolecules. These diseases typically result in the accumulation ofun-degraded molecules in the lysosomes, resulting in increased numbersof storage granules (also termed storage vesicles). These diseases andvarious examples are described in more detail below.

Polypeptide: As used herein, a “polypeptide”, generally speaking, is astring of at least two amino acids attached to one another by a peptidebond. In some embodiments, a polypeptide may include at least 3-5 aminoacids, each of which is attached to others by way of at least onepeptide bond. Those of ordinary skill in the art will appreciate thatpolypeptides sometimes include “non-natural” amino acids or otherentities that nonetheless are capable of integrating into a polypeptidechain, optionally.

Replacement enzyme: As used herein, the term “replacement enzyme” refersto any enzyme that can act to replace at least in part the deficient ormissing enzyme in a disease to be treated. In some embodiments, the term“replacement enzyme” refers to any enzyme that can act to replace atleast in part the deficient or missing lysosomal enzyme in a lysosomalstorage disease to be treated. In some emebodiments, a replacementenzyme is capable of reducing accumulated materials in mammalianlysosomes or that can rescue or ameliorate one or more lysosomal storagedisease symptoms. Replacement enzymes suitable for the invention includeboth wild-type or modified lysosomal enzymes and can be produced usingrecombinant and synthetic methods or purified from nature sources. Areplacement enzyme can be a recombinant, synthetic, gene-activated ornatural enzyme.

Soluble: As used herein, the term “soluble” refers to the ability of atherapeutic agent to form a homogenous solution. In some embodiments,the solubility of the therapeutic agent in the solution into which it isadministered and by which it is transported to the target site of action(e.g., the cells and tissues of the brain) is sufficient to permit thedelivery of a therapeutically effective amount of the therapeutic agentto the targeted site of action. Several factors can impact thesolubility of the therapeutic agents. For example, relevant factorswhich may impact protein solubility include ionic strength, amino acidsequence and the presence of other co-solubilizing agents or salts(e.g., calcium salts). In some embodiments, the pharmaceuticalcompositions are formulated such that calcium salts are excluded fromsuch compositions. In some embodiments, therapeutic agents in accordancewith the present invention are soluble in its correspondingpharmaceutical composition. It will be appreciated that, while isotonicsolutions are generally preferred for parenterally administered drugs,the use of isotonic solutions may limit adequate solubility for sometherapeutic agents and, in particular some proteins and/or enzymes.Slightly hypertonic solutions (e.g., up to 175 mM sodium chloride in 5mM sodium phosphate at pH 7.0) and sugar-containing solutions (e.g., upto 2% sucrose in 5 mM sodium phosphate at pH 7.0) have been demonstratedto be well tolerated in monkeys. For example, the most common approvedCNS bolus formulation composition is saline (150 mM NaCl in water).

Stability: As used herein, the term “stable” refers to the ability ofthe therapeutic agent (e.g., a recombinant enzyme) to maintain itstherapeutic efficacy (e.g., all or the majority of its intendedbiological activity and/or physiochemical integrity) over extendedperiods of time. The stability of a therapeutic agent, and thecapability of the pharmaceutical composition to maintain stability ofsuch therapeutic agent, may be assessed over extended periods of time(e.g., for at least 1, 3, 6, 12, 18, 24, 30, 36 months or more). Ingeneral, pharmaceutical compositions described herein have beenformulated such that they are capable of stabilizing, or alternativelyslowing or preventing the degradation, of one or more therapeutic agentsformulated therewith (e.g., recombinant proteins). In the context of aformulation a stable formulation is one in which the therapeutic agenttherein essentially retains its physical and/or chemical integrity andbiological activity upon storage and during processes (such asfreeze/thaw, mechanical mixing and lyophilization). For proteinstability, it can be measure by formation of high molecular weight (HMW)aggregates, loss of enzyme activity, generation of peptide fragments andshift of charge profiles.

Subject: As used herein, the term “subject” means any mammal, includinghumans. In certain embodiments of the present invention the subject isan adult, an adolescent or an infant. Also contemplated by the presentinvention are the administration of the pharmaceutical compositionsand/or performance of the methods of treatment in-utero.

Substantial homology: The phrase “substantial homology” is used hereinto refer to a comparison between amino acid or nucleic acid sequences.As will be appreciated by those of ordinary skill in the art, twosequences are generally considered to be “substantially homologous” ifthey contain homologous residues in corresponding positions. Homologousresidues may be identical residues. Alternatively, homologous residuesmay be non-identical residues will appropriately similar structuraland/or functional characteristics. For example, as is well known bythose of ordinary skill in the art, certain amino acids are typicallyclassified as “hydrophobic” or “hydrophilic” amino acids, and/or ashaving “polar” or “non-polar” side chains Substitution of one amino acidfor another of the same type may often be considered a “homologous”substitution.

As is well known in this art, amino acid or nucleic acid sequences maybe compared using any of a variety of algorithms, including thoseavailable in commercial computer programs such as BLASTN for nucleotidesequences and BLASTP, gapped BLAST, and PSI-BLAST for amino acidsequences. Exemplary such programs are described in Altschul, et al.,Basic local alignment search tool, J. Mol. Biol., 215(3): 403-410, 1990;Altschul, et al., Methods in Enzymology; Altschul, et al., “Gapped BLASTand PSI-BLAST: a new generation of protein database search programs”,Nucleic Acids Res. 25:3389-3402, 1997; Baxevanis, et al.,Bioinformatics: A Practical Guide to the Analysis of Genes and Proteins,Wiley, 1998; and Misener, et al., (eds.), Bioinformatics Methods andProtocols (Methods in Molecular Biology, Vol. 132), Humana Press, 1999.In addition to identifying homologous sequences, the programs mentionedabove typically provide an indication of the degree of homology. In someembodiments, two sequences are considered to be substantially homologousif at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99% or more of their corresponding residues arehomologous over a relevant stretch of residues. In some embodiments, therelevant stretch is a complete sequence. In some embodiments, therelevant stretch is at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60,65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300,325, 350, 375, 400, 425, 450, 475, 500 or more residues.

Substantial identity: The phrase “substantial identity” is used hereinto refer to a comparison between amino acid or nucleic acid sequences.As will be appreciated by those of ordinary skill in the art, twosequences are generally considered to be “substantially identical” ifthey contain identical residues in corresponding positions. As is wellknown in this art, amino acid or nucleic acid sequences may be comparedusing any of a variety of algorithms, including those available incommercial computer programs such as BLASTN for nucleotide sequences andBLASTP, gapped BLAST, and PSI-BLAST for amino acid sequences. Exemplarysuch programs are described in Altschul, et al., Basic local alignmentsearch tool, J. Mol. Biol., 215(3): 403-410, 1990; Altschul, et al.,Methods in Enzymology; Altschul et al., Nucleic Acids Res. 25:3389-3402,1997; Baxevanis et al., Bioinformatics: A Practical Guide to theAnalysis of Genes and Proteins, Wiley, 1998; and Misener, et al.,(eds.), Bioinformatics Methods and Protocols (Methods in MolecularBiology, Vol. 132), Humana Press, 1999. In addition to identifyingidentical sequences, the programs mentioned above typically provide anindication of the degree of identity. In some embodiments, two sequencesare considered to be substantially identical if at least 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,99% or more of their corresponding residues are identical over arelevant stretch of residues. In some embodiments, the relevant stretchis a complete sequence. In some embodiments, the relevant stretch is atleast 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400,425, 450, 475, 500 or more residues.

Synthetic CSF: As used herein, the term “synthetic CSF” refers to asolution that has pH, electrolyte composition, glucose content andosmalarity consistent with the cerebrospinal fluid. Synthetic CSF isalso referred to as artifical CSF. In some embodiments, synthetic CSF isan Elliott's B solution.

Suitable for CNS delivery: As used herein, the phrase “suitable for CNSdelivery” or “suitable for intrathecal delivery” as it relates to thepharmaceutical compositions of the present invention generally refers tothe stability, tolerability, and solubility properties of suchcompositions, as well as the ability of such compositions to deliver aneffective amount of the therapeutic agent contained therein to thetargeted site of delivery (e.g., the CSF or the brain).

Target tissues: As used herein, the term “target tissues” refers to anytissue that is affected by the lysosomal storage disease to be treatedor any tissue in which the deficient lysosomal enzyme is normallyexpressed. In some embodiments, target tissues include those tissues inwhich there is a detectable or abnormally high amount of enzymesubstrate, for example stored in the cellular lysosomes of the tissue,in patients suffering from or susceptible to the lysosomal storagedisease. In some embodiments, target tissues include those tissues thatdisplay disease-associated pathology, symptom, or feature. In someembodiments, target tissues include those tissues in which the deficientlysosomal enzyme is normally expressed at an elevated level. As usedherein, a target tissue may be a brain target tissue, a spinal cordtarget tissue an/or a peripheral target tissue. Exemplary target tissuesare described in detail below.

Therapeutic moiety: As used herein, the term “therapeutic moiety” refersto a portion of a molecule that renders the therapeutic effect of themolecule. In some embodiments, a therapeutic moiety is a polypeptidehaving therapeutic activity.

Therapeutically effective amount: As used herein, the term“therapeutically effective amount” refers to an amount of a therapeuticprotein (e.g., replacement enzyme) which confers a therapeutic effect onthe treated subject, at a reasonable benefit/risk ratio applicable toany medical treatment. The therapeutic effect may be objective (i.e.,measurable by some test or marker) or subjective (i.e., subject gives anindication of or feels an effect). In particular, the “therapeuticallyeffective amount” refers to an amount of a therapeutic protein orcomposition effective to treat, ameliorate, or prevent a desired diseaseor condition, or to exhibit a detectable therapeutic or preventativeeffect, such as by ameliorating symptoms associated with the disease,preventing or delaying the onset of the disease, and/or also lesseningthe severity or frequency of symptoms of the disease. A therapeuticallyeffective amount is commonly administered in a dosing regimen that maycomprise multiple unit doses. For any particular therapeutic protein, atherapeutically effective amount (and/or an appropriate unit dose withinan effective dosing regimen) may vary, for example, depending on routeof administration, on combination with other pharmaceutical agents.Also, the specific therapeutically effective amount (and/or unit dose)for any particular patient may depend upon a variety of factorsincluding the disorder being treated and the severity of the disorder;the activity of the specific pharmaceutical agent employed; the specificcomposition employed; the age, body weight, general health, sex and dietof the patient; the time of administration, route of administration,and/or rate of excretion or metabolism of the specific fusion proteinemployed; the duration of the treatment; and like factors as is wellknown in the medical arts.

Tolerable: As used herein, the terms “tolerable” and “tolerability”refer to the ability of the pharmaceutical compositions of the presentinvention to not elicit an adverse reaction in the subject to whom suchcomposition is administered, or alternatively not to elicit a seriousadverse reaction in the subject to whom such composition isadministered. In some embodiments, the pharmaceutical compositions ofthe present invention are well tolerated by the subject to whom suchcompositions is administered.

Treatment: As used herein, the term “treatment” (also “treat” or“treating”) refers to any administration of a therapeutic protein (e.g.,lysosomal enzyme) that partially or completely alleviates, ameliorates,relieves, inhibits, delays onset of, reduces severity of and/or reducesincidence of one or more symptoms or features of a particular disease,disorder, and/or condition (e.g., Hunters syndrome, Sanfilippo Bsyndrome). Such treatment may be of a subject who does not exhibit signsof the relevant disease, disorder and/or condition and/or of a subjectwho exhibits only early signs of the disease, disorder, and/orcondition. Alternatively or additionally, such treatment may be of asubject who exhibits one or more established signs of the relevantdisease, disorder and/or condition.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides, among other things, improved methods andcompositions for effective direct delivery of a therapeutic agent to thecentral nervous system (CNS). As discussed above, the present inventionis based on unexpected discovery that a replacement enzyme (e.g., an I2Sprotein) for a lysososmal storage disease (e.g., Hunters Syndrome) canbe directly introduced into the cerebrospinal fluid (CSF) of a subjectin need of treatment at a high concentration without inducingsubstantial adverse effects in the subject. More surprisingly, thepresent inventors found that the replacement enzyme may be delivered ina simple saline or buffer-based formulation, without using syntheticCSF. Even more unexpectedly, intrathecal delivery according to thepresent invention does not result in substantial adverse effects, suchas severe immune response, in the subject. Therefore, in someembodiments, intrathecal delivery according to the present invention maybe used in absence of concurrent immunosuppressant therapy (e.g.,without induction of immune tolerance by pre-treatment orpre-conditioning).

In some embodiments, intrathecal delivery according to the presentinvention permits efficient diffusion across various brain tissuesresulting in effective delivery of the replacement enzyme in varioustarget brain tissues in surface, shallow and/or deep brain regions. Insome embodiments, intrathecal delivery according to the presentinvention resulted in sufficient amount of replacement enzymes enteringthe peripheral circulation. As a result, in some cases, intrathecaldelivery according to the present invention resulted in delivery of thereplacement enzyme in peripheral tissues, such as liver, heart, spleenand kidney. This discovery is unexpected and can be particular usefulfor the treatment of lysosomal storage diseases that have both CNS andperipheral components, which would typically require both regularintrathecal administration and intravenous administration. It iscontemplated that intrathecal delivery according to the presentinvention may allow reduced dosing and/or frequency of iv injectionwithout compromising therapeutic effects in treating peripheralsymptoms.

The present invention provides various unexpected and beneficialfeatures that allow efficient and convenient delivery of replacementenzymes to various brain target tissues, resulting in effectivetreatment of lysosomal storage diseases that have CNS indications.

Various aspects of the invention are described in detail in thefollowing sections. The use of sections is not meant to limit theinvention. Each section can apply to any aspect of the invention. Inthis application, the use of “or” means “and/or” unless statedotherwise.

Replacement Enzymes

Iduronate-2-Sulfatase (I2S) Protein

In some embodiments, inventive methods and compositions provided by thepresent invention are used to deliver an Iduronate-2-sulfatase (I2S)protein to the CNS for treatment of Hunters Syndrome. A suitable I2Sprotein can be any molecule or a portion of a molecule that cansubstitute for naturally-occurring Iduronate-2-sulfatase (I2S) proteinactivity or rescue one or more phenotypes or symptoms associated withI2S-deficiency. In some embodiments, a replacement enzyme suitable forthe invention is a polypeptide having an N-terminus and a C-terminus andan amino acid sequence substantially similar or identical to maturehuman I2S protein.

Typically, the human I2S protein is produced as a precursor form. Theprecursor form of human I2S contains a signal peptide (amino acidresidues 1-25 of the full length precursor), a pro-peptide (amino acidresidues 26-33 of the full length precursor), and a chain (residues34-550 of the full length precursor) that may be further processed intothe 42 kDa chain (residues 34-455 of the full length precursor) and the14 kDa chain (residues 446-550 of the full length precursor). Typically,the precursor form is also referred to as full-length precursor orfull-length I2S protein, which contains 550 amino acids. The amino acidsequences of the mature form (SEQ ID NO:1) having the signal peptideremoved and full-length precursor (SEQ ID NO:2) of a typical wild-typeor naturally-occurring human I2S protein are shown in Table 1.

TABLE 1 Human Iduronate-2-sulfatase MatureSETQANSTTDALNVLLIIVDDLRPSLGCYGDKLVRSP FormNIDQLASHSLLFQNAFAQQAVCAPSRVSFLTGRRPDTTRLYDFNSYWRVHAGNFSTIPQYFKENGYVTMSVGKVFHPGISSNHTDDSPYSWSFPPYHPSSEKYENTKTCRGPDGELHANLLCPVDVLDVPEGTLPDKQSTEQATQLLEKMKTSASPFFLAVGYHKPHIPFRYPKEFQKLYPLENITLAPDPEVPDGLPPVAYNPWMDIRQREDVQALNISVPYGPIPVDFQRKIRQSYFASVSYLDTQVGRLLSALDDLQLANSTIIAFTSDHGWALGEHGEWAKYSNFDVATHVPLIFYVPGRTASLPEAGEKLFPYLDPFDSASQLMEPGRQSMDLVELVSLFPTLAGLAGLQVPPRCPVPSFHVELCREGKNLLKHFRFRDLEEDPYLPGNPRELIAYSQYPRPSDIPQWNSDKPSLKDIKIMGYSIRTIDYRYTVWVGFNPDEFLANFSDIHAGELYFVDSDPLQDHNMYNDSQGGD LFQLLMP(SEQ ID NO: 1) Full-MPPPRTGRGLLWLGLVLSSVCVALGSETQANSTTDAL LengthNVLLIIVDDLRPSLGCYGDKLVRSPNIDQLASHSLLF PrecursorQNAFAQQAVCAPSRVSFLTGRRPDTTRLYDFNSYWRVHAGNFSTIPQYFKENGYVTMSVGKVFHPGISSNHTDDSPYSWSFPPYHPSSEKYENTKTCRGPDGELHANLLCPVDVLDVPEGTLPDKQSTEQATQLLEKMKTSASPFFLAVGYHKPHIPFRYPKEFQKLYPLENITLAPDPEVPDGLPPVAYNPWMDIRQREDVQALNISVPYGPIPVDFQRKIRQSYFASVSYLDTQVGRLLSALDDLQLANSTIIAFTSDHGWALGEHGEWAKYSNFDVATHVPLIFYVPGRTASLPEAGEKLFPYLDPFDSASQLMEPGRQSMDLVELVSLFPTLAGLAGLQVPPRCPVPSFHVELCREGKNLLKHFRFRDLEEDPYLPGNPRELIAYSQYPRPSDIPQWNSDKPSLKDIKIMGYSIRTIDYRYTVWVGFNPDEFLANFSDIHAGELYFVDSDPLQDHNMYNDSQGGDLFQLLMP(SEQ  ID NO: 2)

Thus, in some embodiments, a replacement enzyme suitable for the presentinvention is mature human I2S protein (SEQ ID NO:1). In someembodiments, a suitable replacement enzyme may be a homologue or ananalogue of mature human I2S protein. For example, a homologue or ananalogue of mature human I2S protein may be a modified mature human I2Sprotein containing one or more amino acid substitutions, deletions,and/or insertions as compared to a wild-type or naturally-occurring I2Sprotein (e.g., SEQ ID NO:1), while retaining substantial I2S proteinactivity. Thus, in some embodiments, a replacement enzyme suitable forthe present invention is substantially homologous to mature human I2Sprotein (SEQ ID NO:1). In some embodiments, a replacement enzymesuitable for the present invention has an amino acid sequence at least50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99% or more homologous to SEQ ID NO:1. In someembodiments, a replacement enzyme suitable for the present invention issubstantially identical to mature human I2S protein (SEQ ID NO:1). Insome embodiments, a replacement enzyme suitable for the presentinvention has an amino acid sequence at least 50%, 55%, 60%, 65%, 70%,75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or moreidentical to SEQ ID NO:1. In some embodiments, a replacement enzymesuitable for the present invention contains a fragment or a portion ofmature human 12S protein.

Alternatively, a replacement enzyme suitable for the present inventionis full-length I2S protein. In some embodiments, a suitable replacementenzyme may be a homologue or an analogue of full-length human I2Sprotein. For example, a homologue or an analogue of full-length humanI2S protein may be a modified full-length human I2S protein containingone or more amino acid substitutions, deletions, and/or insertions ascompared to a wild-type or naturally-occurring full-length I2S protein(e.g., SEQ ID NO:2), while retaining substantial I2S protein activity.Thus, In some embodiments, a replacement enzyme suitable for the presentinvention is substantially homologous to full-length human I2S protein(SEQ ID NO:2). In some embodiments, a replacement enzyme suitable forthe present invention has an amino acid sequence at least 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,99% or more homologous to SEQ ID NO:2. In some embodiments, areplacement enzyme suitable for the present invention is substantiallyidentical to SEQ ID NO:2. In some embodiments, a replacement enzymesuitable for the present invention has an amino acid sequence at least50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99% or more identical to SEQ ID NO:2. In someembodiments, a replacement enzyme suitable for the present inventioncontains a fragment or a portion of full-length human I2S protein. Asused herein, a full-length I2S protein typically contains signal peptidesequence.

Other Lysosomal Storage Diseases and Replacement Enzymes

It is contemplated that inventive methods and compositions according tothe present invention can be used to treat other lysosomal storagediseases, in particular those lysosomal storage diseases having CNSetiology and/or symptoms, including, but are not limited to,aspartylglucosaminuria, cholesterol ester storage disease, Wolmandisease, cystinosis, Danon disease, Fabry disease, Farberlipogranulomatosis, Farber disease, fucosidosis, galactosialidosis typesI/II, Gaucher disease types I/II/III, globoid cell leukodystrophy,Krabbe disease, glycogen storage disease II, Pompe disease,GM1-gangliosidosis types I/II/III, GM2-gangliosidosis type I, Tay Sachsdisease, GM2-gangliosidosis type II, Sandhoff disease,GM2-gangliosidosis, α-mannosidosis types I/II, .beta.-mannosidosis,metachromatic leukodystrophy, mucolipidosis type I, sialidosis typesI/II, mucolipidosis types II/III, I-cell disease, mucolipidosis typeIIIC pseudo-Hurler polydystrophy, mucopolysaccharidosis type I,mucopolysaccharidosis type II, mucopolysaccharidosis type IIIA,Sanfilippo syndrome, mucopolysaccharidosis type TIM,mucopolysaccharidosis type IIIC, mucopolysaccharidosis type IIID,mucopolysaccharidosis type IVA, Morquio syndrome, mucopolysaccharidosistype IVB, mucopolysaccharidosis type VI, mucopolysaccharidosis type VII,Sly syndrome, mucopolysaccharidosis type IX, multiple sulfatasedeficiency, neuronal ceroid lipofuscinosis, CLN1 Batten disease, CLN2Batten diseae, Niemann-Pick disease types A/B, Niemann-Pick disease typeC1, Niemann-Pick disease type C2, pycnodysostosis, Schindler diseasetypes I/II, Gaucher disease and sialic acid storage disease.

A detailed review of the genetic etiology, clinical manifestations, andmolecular biology of the lysosomal storage diseases are detailed inScriver et al., eds., The Metabolic and Molecular Basis of InheritedDisease, 7.sup.th Ed., Vol. II, McGraw Hill, (1995). Thus, the enzymesdeficient in the above diseases are known to those of skill in the art,some of these are exemplified in Table 2 below:

TABLE 2 Substance Disease Name Enzyme Deficiency Stored Pompe DiseaseAcid-a1, 4- Glycogen α□1-4 Glucosidase linked Oligosaccharides GM1Gangliodsidosis β-Galactosidase GM₁ Gangliosides Tay-Sachs Diseaseβ-Hexosaminidase A GM₂ Ganglioside GM2 Gangliosidosis: GM₂ Activator GM₂Ganglioside AB Variant Protein Sandhoff Disease β-Hexosaminidase GM₂Ganglioside A&B Fabry Disease α-Galactosidase A Globosides GaucherDisease Glucocerebrosidase Glucosylceramide Metachromatic ArylsulfataseA Sulphatides Leukodystrophy Krabbe Disease GalactosylceramidaseGalactocerebroside Niemann Pick, Types Acid Sphingomyelin A & BSphingomyelinase Niemann-Pick, Type Cholesterol Sphingomyelin CEsterification Defect Niemann-Pick, Type Unknown Sphingomyelin D FarberDisease Acid Ceramidase Ceramide Wolman Disease Acid Lipase CholesterylEsters Hurler Syndrome α-L-Iduronidase Heparan & (MPS IH) DermatanSulfates Scheie Syndrome α-L-Iduronidase Heparan & (MPS IS) Dermatan,Sulfates Hurler-Scheie α-L-Iduronidase Heparan & (MPS IH/S) DermatanSulfates Hunter Syndrome Iduronate Sulfatase Heparan & (MPS II) DermatanSulfates Sanfilippo A Heparan N-Sulfatase Heparan (MPS IIIA) SulfateSanfilippo B α-N- Heparan (MPS IIIB) Acetylglucosaminidase SulfateSanfilippo C Acetyl-CoA- Heparan (MPS IIIC) Glucosaminide SulfateAcetyltransferase Sanfilippo D N-Acetylglucosamine- Heparan (MPS IIID)6-Sulfatase Sulfate Morquio B β-Galactosidase Keratan (MPS IVB) SulfateMaroteaux-Lamy Arylsulfatase B Dermatan (MPS VI) Sulfate Sly Syndromeβ-Glucuronidase (MPS VII) α-Mannosidosis α-□Mannosidase Mannose/Oligosaccharides β-Mannosidosis β-Mannosidase Mannose/ OligosaccharidesFucosidosis α-L-Fucosidase Fucosyl Oligosaccharides Aspartyl-N-Aspartyl-β- Aspartylglucosamine glucosaminuria GlucosaminidaseAsparagines Sialidosis α-Neuraminidase Sialyloligosaccharides(Mucolipidosis I) Galactosialidosis Lysosomal ProtectiveSialyloligosaccharides (Goldberg Syndrome) Protein Deficiency SchindlerDisease α-N-Acetyl- Galactosaminidase Mucolipidosis II (I-N-Acetylglucosamine- Heparan Sulfate Cell Disease) 1-PhosphotransferaseMucolipidosis III Same as ML II (Pseudo-Hurler Polydystrophy) CystinosisCystine Transport Free Cystine Protein Salla Disease Sialic AcidTransport Free Sialic Acid and Protein Glucuronic Acid Infantile SialicAcid Sialic Acid Transport Free Sialic Acid and Storage Disease ProteinGlucuronic Acid Infantile Neuronal Palmitoyl-Protein Lipofuscins CeroidLipofuscinosis Thioesterase Mucolipidosis IV Unknown Gangliosides &Hyaluronic Acid Prosaposin Saposins A, B, C or D

Inventive methods according to the present invention may be used todeliver various other replacement enzymes. As used herein, replacementenzymes suitable for the present invention may include any enzyme thatcan act to replace at least partial activity of the deficient or missinglysosomal enzyme in a lysosomal storage disease to be treated. In someembodiments, a replacement enzyme is capable of reducing accumulatedsubstance in lysosomes or that can rescue or ameliorate one or morelysosomal storage disease symptoms.

In some embodiments, a suitable replacement enzyme may be any lysosomalenzyme known to be associated with the lysosomal storage disease to betreated. In some embodiments, a suitable replacement enzyme is an enzymeselected from the enzyme listed in Table 2 above.

In some embodiments, a replacement enzyme suitable for the invention mayhave a wild-type or naturally occurring sequence. In some embodiments, areplacement enzyme suitable for the invention may have a modifiedsequence having substantial homology or identify to the wild-type ornaturally-occurring sequence (e.g., having at least 50%, 55%, 60%, 65%,70%, 75%, 80%, 85%, 90%, 95%, 98% sequence identity to the wild-type ornaturally-occurring sequence).

A replacement enzyme suitable for the present invention may be producedby any available means. For example, replacement enzymes may berecombinantly produced by utilizing a host cell system engineered toexpress a replacement enzyme-encoding nucleic acid. Alternatively oradditionally, replacement enzymes may be produced by activatingendogenous genes. Alternatively or additionally, replacement enzymes maybe partially or fully prepared by chemical synthesis. Alternatively oradditionally, replacements enzymes may also be purified from naturalsources.

Where enzymes are recombinantly produced, any expression system can beused. To give but a few examples, known expression systems include, forexample, egg, baculovirus, plant, yeast, or mammalian cells.

In some embodiments, enzymes suitable for the present invention areproduced in mammalian cells. Non-limiting examples of mammalian cellsthat may be used in accordance with the present invention include BALB/cmouse myeloma line (NSO/l, ECACC No: 85110503); human retinoblasts(PER.C6, CruCell, Leiden, The Netherlands); monkey kidney CV1 linetransformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line(293 or 293 cells subcloned for growth in suspension culture, Graham etal., J. Gen Virol., 36:59, 1977); human fibrosarcoma cell line (e.g.,HT1080); baby hamster kidney cells (BHK, ATCC CCL 10); Chinese hamsterovary cells +/−DHFR (CHO, Urlaub and Chasin, Proc. Natl. Acad. Sci. USA,77:4216, 1980); mouse sertoli cells (TM4, Mather, Biol. Reprod.,23:243-251, 1980); monkey kidney cells (CV1 ATCC CCL 70); African greenmonkey kidney cells (VERO-76, ATCC CRL-1 587); human cervical carcinomacells (HeLa, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34);buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (W138,ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor(MMT 060562, ATCC CCL51); TRI cells (Mather et al., Annals N.Y. Acad.Sci., 383:44-68, 1982); MRC 5 cells; FS4 cells; and a human hepatomaline (Hep G2).

In some embodiments, inventive methods according to the presentinvention are used to deliver replacement enzymes produced from humancells. In some embodiments, inventive methods according to the presentinvention are used to deliver replacement enzymes produced from CHOcells.

In some embodiments, replacement enzymes delivered using a method of theinvention contain a moiety that binds to a receptor on the surface ofbrain cells to facilitate cellular uptake and/or lysosomal targeting.For example, such a receptor may be the cation-independentmannose-6-phosphate receptor (CI-MPR) which binds themannose-6-phosphate (M6P) residues. In addition, the CI-MPR also bindsother proteins including IGF-II. In some embodiments, a replacementenzyme suitable for the present invention contains M6P residues on thesurface of the protein. In some embodiments, a replacement enzymesuitable for the present invention may contain bis-phosphorylatedoligosaccharides which have higher binding affinity to the CI-MPR. Insome embodiments, a suitable enzyme contains up to about an average ofabout at least 20% bis-phosphorylated oligosaccharides per enzyme. Inother embodiments, a suitable enzyme may contain about 10%, 15%, 18%,20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% bis-phosphorylatedoligosaccharides per enzyme. While such bis-phosphorylatedoligosaccharides may be naturally present on the enzyme, it should benoted that the enzymes may be modified to possess such oligosaccharides.For example, suitable replacement enzymes may be modified by certainenzymes which are capable of catalyzing the transfer ofN-acetylglucosamine-L-phosphate from UDP-GlcNAc to the 6′ position ofα-1,2-linked mannoses on lysosomal enzymes. Methods and compositions forproducing and using such enzymes are described by, for example, Canfieldet al. in U.S. Pat. Nos. 6,537,785, and 6,534,300, each incorporatedherein by reference.

In some embodiments, replacement enzymes for use in the presentinvention may be conjugated or fused to a lysosomal targeting moietythat is capable of binding to a receptor on the surface of brain cells.A suitable lysosomal targeting moiety can be IGF-I, IGF-II, RAP, p97,and variants, homologues or fragments thereof (e.g., including thosepeptide having a sequence at least 70%, 75%, 80%, 85%, 90%, or 95%identical to a wild-type mature human IGF-I, IGF-II, RAP, p97 peptidesequence).

In some embodiments, replacement enzymes suitable for the presentinvention have not been modified to enhance delivery or transport ofsuch agents across the BBB and into the CNS.

In some embodiments, a therapeutic protein includes a targeting moiety(e.g., a lysosome targeting sequence) and/or a membrane-penetratingpeptide. In some embodiments, a targeting sequence and/or amembrane-penetrating peptide is an intrinsic part of the therapeuticmoiety (e.g., via a chemical linkage, via a fusion protein). In someembodiments, a targeting sequence contains a mannose-6-phosphate moiety.In some embodiments, a targeting sequence contains an IGF-I moiety. Insome embodiments, a targeting sequence contains an IGF-II moiety.

Formulations

In some embodiments, desired enzymes are delivered in stableformulations for intrathecal delivery. Certain embodiments of theinvention are based, at least in part, on the discovery that variousformulations disclosed herein facilitate the effective delivery anddistribution of one or more therapeutic agents (e.g., an I2S enzyme) totargeted tissues, cells and/or organelles of the CNS. Among otherthings, formulations described herein are capable of solubilizing highconcentrations of therapeutic agents (e.g., an I2S enzyme) and aresuitable for the delivery of such therapeutic agents to the CNS ofsubjects for the treatment of diseases having a CNS component and/oretiology (e.g., Hunters Syndrome). The compositions described herein arefurther characterized by improved stability and improved tolerabilitywhen administered to the CNS of a subject (e.g., intrathecally) in needthereof.

Before the present invention, traditional unbuffered isotonic saline andElliott's B solution, which is artificial CSF, were typically used forintrathecal delivery. A comparison depicting the compositions of CSFrelative to Elliott's B solution is included in Table 3 below. As shownin Table 3, the concentration of Elliot's B Solution closely parallelsthat of the CSF. Elliott's B Solution, however contains a very lowbuffer concentration and accordingly may not provide the adequatebuffering capacity needed to stabilize therapeutic agents (e.g.,proteins), especially over extended periods of time (e.g., duringstorage conditions). Furthermore, Elliott's B Solution contains certainsalts which may be incompatible with the formulations intended todeliver some therapeutic agents, and in particular proteins or enzymes.For example, the calcium salts present in Elliott's B Solution arecapable of mediating protein precipitation and thereby reducing thestability of the formulation.

TABLE 3 Na⁺ K⁺ Ca⁺⁺ Mg⁺⁺ HCO3⁻ Cl⁻ Phosphorous Glucose Solution mEq/LmEq/L mEq/L mEq/L mEq/L mEq/L pH mg/L mg/L CSF 117-137 2.3 2.2 2.2 22.9113-127 7.31 1.2-2.1 45-80 Elliott's 149 2.6 2.7 2.4 22.6 132 6.0-7.52.3 80 B Sol'n

Thus, in some embodiments, formulations suitable for CNS deliveryaccording to the present invention are not synthetic or artificial CSF.

In some embodiments, formulations for CNS delivery have been formulatedsuch that they are capable of stabilizing, or alternatively slowing orpreventing the degradation, of a therapeutic agent formulated therewith(e.g., an I2S enzyme). As used herein, the term “stable” refers to theability of the therapeutic agent (e.g., an I2S enzyme) to maintain itstherapeutic efficacy (e.g., all or the majority of its intendedbiological activity and/or physiochemical integrity) over extendedperiods of time. The stability of a therapeutic agent, and thecapability of the pharmaceutical composition to maintain stability ofsuch therapeutic agent, may be assessed over extended periods of time(e.g., preferably for at least 1, 3, 6, 12, 18, 24, 30, 36 months ormore). In the context of a formulation a stable formulation is one inwhich the therapeutic agent therein essentially retains its physicaland/or chemical integrity and biological activity upon storage andduring processes (such as freeze/thaw, mechanical mixing andlyophilization). For protein stability, it can be measure by formationof high molecular weight (BMW) aggregates, loss of enzyme activity,generation of peptide fragments and shift of charge profiles.

Stability of the therapeutic agent is of particular importance.Stability of the therapeutic agent may be further assessed relative tothe biological activity or physiochemical integrity of the therapeuticagent over extended periods of time. For example, stability at a giventime point may be compared against stability at an earlier time point(e.g., upon formulation day 0) or against unformulated therapeutic agentand the results of this comparison expressed as a percentage.Preferably, the pharmaceutical compositions of the present inventionmaintain at least 100%, at least 99%, at least 98%, at least 97% atleast 95%, at least 90%, at least 85%, at least 80%, at least 75%, atleast 70%, at least 65%, at least 60%, at least 55% or at least 50% ofthe therapeutic agent's biological activity or physiochemical integrityover an extended period of time (e.g., as measured over at least about6-12 months, at room temperature or under accelerated storageconditions).

In some embodiments, therapeutic agents (e.g., desired enzymes) aresoluble in formulations of the present invention. The term “soluble” asit relates to the therapeutic agents of the present invention refer tothe ability of such therapeutic agents to form a homogenous solution.Preferably the solubility of the therapeutic agent in the solution intowhich it is administered and by which it is transported to the targetsite of action (e.g., the cells and tissues of the brain) is sufficientto permit the delivery of a therapeutically effective amount of thetherapeutic agent to the targeted site of action. Several factors canimpact the solubility of the therapeutic agents. For example, relevantfactors which may impact protein solubility include ionic strength,amino acid sequence and the presence of other co-solubilizing agents orsalts (e.g., calcium salts.) In some embodiments, the pharmaceuticalcompositions are formulated such that calcium salts are excluded fromsuch compositions.

Suitable formulations, in either aqueous, pre-lyophilized, lyophilizedor reconstituted form, may contain a therapeutic agent of interest atvarious concentrations. In some embodiments, formulations may contain aprotein or therapeutic agent of interest at a concentration in the rangeof about 0.1 mg/ml to 100 mg/ml (e.g., about 0.1 mg/ml to 80 mg/ml,about 0.1 mg/ml to 60 mg/ml, about 0.1 mg/ml to 50 mg/ml, about 0.1mg/ml to 40 mg/ml, about 0.1 mg/ml to 30 mg/ml, about 0.1 mg/ml to 25mg/ml, about 0.1 mg/ml to 20 mg/ml, about 0.1 mg/ml to 60 mg/ml, about0.1 mg/ml to 50 mg/ml, about 0.1 mg/ml to 40 mg/ml, about 0.1 mg/ml to30 mg/ml, about 0.1 mg/ml to 25 mg/ml, about 0.1 mg/ml to 20 mg/ml,about 0.1 mg/ml to 15 mg/ml, about 0.1 mg/ml to 10 mg/ml, about 0.1mg/ml to 5 mg/ml, about 1 mg/ml to 10 mg/ml, about 1 mg/ml to 20 mg/ml,about 1 mg/ml to 40 mg/ml, about 5 mg/ml to 100 mg/ml, about 5 mg/ml to50 mg/ml, or about 5 mg/ml to 25 mg/ml). In some embodiments,formulations according to the invention may contain a therapeutic agentat a concentration of approximately 1 mg/ml, 5 mg/ml, 10 mg/ml, 15mg/ml, 20 mg/ml, 25 mg/ml, 30 mg/ml, 40 mg/ml, 50 mg/ml, 60 mg/ml, 70mg/ml, 80 mg/ml, 90 mg/ml, or 100 mg/ml.

The formulations of the present invention are characterized by theirtolerability either as aqueous solutions or as reconstituted lyophilizedsolutions. As used herein, the terms “tolerable” and “tolerability”refer to the ability of the pharmaceutical compositions of the presentinvention to not elicit an adverse reaction in the subject to whom suchcomposition is administered, or alternatively not to elicit a seriousadverse reaction in the subject to whom such composition isadministered. In some embodiments, the pharmaceutical compositions ofthe present invention are well tolerated by the subject to whom suchcompositions is administered.

Many therapeutic agents, and in particular the proteins and enzymes ofthe present invention, require controlled pH and specific excipients tomaintain their solubility and stability in the pharmaceuticalcompositions of the present invention. Table 4 below identifies typicalexemplary aspects of protein formulations considered to maintain thesolubility and stability of the protein therapeutic agents of thepresent invention.

TABLE 4 Parameter Typical Range/Type Rationale pH 5 to 7.5 For stabilitySometimes also for solubility Buffer type acetate, succinate, Tomaintain optimal pH citrate, histidine, May also affect stabilityphosphate or Tris Buffer 5-50 mM To maintain pH concentration May alsostabilize or add ionic strength Tonicifier NaCl, sugars, To renderiso-osmotic or mannitol isotonic solutions Surfactant Polysorbate 20, Tostabilize against interfaces polysorbate 80 and shear Other Amino acidsFor enhanced solubility or (e.g. arginine) stability at tens to hundredsof mM

Buffers

The pH of the formulation is an additional factor which is capable ofaltering the solubility of a therapeutic agent (e.g., an enzyme orprotein) in an aqueous formulation or for a pre-lyophilizationformulation. Accordingly the formulations of the present inventionpreferably comprise one or more buffers. In some embodiments the aqueousformulations comprise an amount of buffer sufficient to maintain theoptimal pH of said composition between about 4.0-8.0 (e.g., about 4.0,4.5, 5.0, 5.5, 6.0, 6.2, 6.4, 6.5, 6.6, 6.8, 7.0, 7.5, or 8.0). In someembodiments, the pH of the formulation is between about 5.0-7.5, betweenabout 5.5-7.0, between about 6.0-7.0, between about 5.5-6.0, betweenabout 5.5-6.5, between about 5.0-6.0, between about 5.0-6.5 and betweenabout 6.0-7.5. Suitable buffers include, for example acetate, citrate,histidine, phosphate, succinate, tris(hydroxymethyl)aminomethane(“Tris”) and other organic acids. The buffer concentration and pH rangeof the pharmaceutical compositions of the present invention are factorsin controlling or adjusting the tolerability of the formulation. In someembodiments, a buffering agent is present at a concentration rangingbetween about 1 mM to about 150 mM, or between about 10 mM to about 50mM, or between about 15 mM to about 50 mM, or between about 20 mM toabout 50 mM, or between about 25 mM to about 50 mM. In some embodiments,a suitable buffering agent is present at a concentration ofapproximately 1 mM, 5 mM, 10 mM, 15 mM, 20 mM, 25 mM, 30 mM, 35 mM, 40mM, 45 mM 50 mM, 75 mM, 100 mM, 125 mM or 150 mM.

Tonicity

In some embodiments, formulations, in either aqueous, pre-lyophilized,lyophilized or reconstituted form, contain an isotonicity agent to keepthe formulations isotonic. Typically, by “isotonic” is meant that theformulation of interest has essentially the same osmotic pressure ashuman blood. Isotonic formulations will generally have an osmoticpressure from about 240 mOsm/kg to about 350 mOsm/kg. Isotonicity can bemeasured using, for example, a vapor pressure or freezing point typeosmometers. Exemplary isotonicity agents include, but are not limitedto, glycine, sorbitol, mannitol, sodium chloride and arginine. In someembodiments, suitable isotonic agents may be present in aqueous and/orpre-lyophilized formulations at a concentration from about 0.01-5%(e.g., 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.75, 1.0, 1.25, 1.5, 2.0,2.5, 3.0, 4.0 or 5.0%) by weight. In some embodiments, formulations forlyophilization contain an isotonicity agent to keep thepre-lyophilization formulations or the reconstituted formulationsisotonic.

While generally isotonic solutions are preferred for parenterallyadministered drugs, the use of isotonic solutions may change solubilityfor some therapeutic agents and in particular some proteins and/orenzymes. Slightly hypertonic solutions (e.g., up to 175 mM sodiumchloride in 5 mM sodium phosphate at pH 7.0) and sugar-containingsolutions (e.g., up to 2% sucrose in 5 mM sodium phosphate at pH 7.0)have been demonstrated to be well tolerated. The most common approvedCNS bolus formulation composition is saline (about 150 mM NaCl inwater).

Stabilizing Agents

In some embodiments, formulations may contain a stabilizing agent, orlyoprotectant, to protect the protein. Typically, a suitable stabilizingagent is a sugar, a non-reducing sugar and/or an amino acid. Exemplarysugars include, but are not limited to, dextran, lactose, mannitol,mannose, sorbitol, raffinose, sucrose and trehalose. Exemplary aminoacids include, but are not limited to, arginine, glycine and methionine.Additional stabilizing agents may include sodium chloride, hydroxyethylstarch and polyvinylpyrolidone. The amount of stabilizing agent in thelyophilized formulation is generally such that the formulation will beisotonic. However, hypertonic reconstituted formulations may also besuitable. In addition, the amount of stabilizing agent must not be toolow such that an unacceptable amount of degradation/aggregation of thetherapeutic agent occurs. Exemplary stabilizing agent concentrations inthe formulation may range from about 1 mM to about 400 mM (e.g., fromabout 30 mM to about 300 mM, and from about 50 mM to about 100 mM), oralternatively, from 0.1% to 15% (e.g., from 1% to 10%, from 5% to 15%,from 5% to 10%) by weight. In some embodiments, the ratio of the massamount of the stabilizing agent and the therapeutic agent is about 1:1.In other embodiments, the ratio of the mass amount of the stabilizingagent and the therapeutic agent can be about 0.1:1, 0.2:1, 0.25:1,0.4:1, 0.5:1, 1:1, 2:1, 2.6:1, 3:1, 4:1, 5:1, 10:1, or 20:1. In someembodiments, suitable for lyophilization, the stabilizing agent is alsoa lyoprotectant.

In some embodiments, liquid formulations suitable for the presentinvention contain amorphous materials. In some embodiments, liquidformulations suitable for the present invention contain a substantialamount of amorphous materials (e.g., sucrose-based formulations). Insome embodiments, liquid formulations suitable for the present inventioncontain partly crystalline/partly amorphous materials.

Bulking Agents

In some embodiments, suitable formulations for lyophilization mayfurther include one or more bulking agents. A “bulking agent” is acompound which adds mass to the lyophilized mixture and contributes tothe physical structure of the lyophilized cake. For example, a bulkingagent may improve the appearance of lyophilized cake (e.g., essentiallyuniform lyophilized cake). Suitable bulking agents include, but are notlimited to, sodium chloride, lactose, mannitol, glycine, sucrose,trehalose, hydroxyethyl starch. Exemplary concentrations of bulkingagents are from about 1% to about 10% (e.g., 1.0%, 1.5%, 2.0%, 2.5%,3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%,9.0%, 9.5%, and 10.0%).

Surfactants

In some embodiments, it is desirable to add a surfactant toformulations. Exemplary surfactants include nonionic surfactants such asPolysorbates (e.g., Polysorbates 20 or 80); poloxamers (e.g., poloxamer188); Triton; sodium dodecyl sulfate (SDS); sodium laurel sulfate;sodium octyl glycoside; lauryl-, myristyl-, linoleyl-, orstearyl-sulfobetaine; lauryl-, myristyl-, linoleyl- orstearyl-sarcosine; linoleyl-, myristyl-, or cetyl-betaine;lauroamidopropyl-, cocamidopropyl-, linoleamidopropyl-,myristamidopropyl-, palmidopropyl-, or isostearamidopropyl-betaine(e.g., lauroamidopropyl); myristarnidopropyl-, palmidopropyl-, orisostearamidopropyl-dimethylamine; sodium methyl cocoyl-, or disodiummethyl ofeyl-taurate; and the MONAQUAT™ series (Mona Industries, Inc.,Paterson, N.J.), polyethyl glycol, polypropyl glycol, and copolymers ofethylene and propylene glycol (e.g., Pluronics, PF68, etc). Typically,the amount of surfactant added is such that it reduces aggregation ofthe protein and minimizes the formation of particulates oreffervescences. For example, a surfactant may be present in aformulation at a concentration from about 0.001-0.5% (e.g., about0.005-0.05%, or 0.005-0.01%). In particular, a surfactant may be presentin a formulation at a concentration of approximately 0.005%, 0.01%,0.02%, 0.1%, 0.2%, 0.3%, 0.4%, or 0.5%, etc. Alternatively, or inaddition, the surfactant may be added to the lyophilized formulation,pre-lyophilized formulation and/or the reconstituted formulation.

Other pharmaceutically acceptable carriers, excipients or stabilizerssuch as those described in Remington's Pharmaceutical Sciences 16thedition, Osol, A. Ed. (1980) may be included in the formulation (and/orthe lyophilized formulation and/or the reconstituted formulation)provided that they do not adversely affect the desired characteristicsof the formulation. Acceptable carriers, excipients or stabilizers arenontoxic to recipients at the dosages and concentrations employed andinclude, but are not limited to, additional buffering agents;preservatives; co-solvents; antioxidants including ascorbic acid andmethionine; chelating agents such as EDTA; metal complexes (e.g.,Zn-protein complexes); biodegradable polymers such as polyesters; and/orsalt-forming counterions such as sodium.

Formulations, in either aqueous, pre-lyophilized, lyophilized orreconstituted form, in accordance with the present invention can beassessed based on product quality analysis, reconstitution time (iflyophilized), quality of reconstitution (if lyophilized), high molecularweight, moisture, and glass transition temperature. Typically, proteinquality and product analysis include product degradation rate analysisusing methods including, but not limited to, size exclusion HPLC(SE-HPLC), cation exchange-HPLC (CEX-HPLC), X-ray diffraction (XRD),modulated differential scanning calorimetry (mDSC), reversed phase HPLC(RP-HPLC), multi-angle light scattering (MALS), fluorescence,ultraviolet absorption, nephelometry, capillary electrophoresis (CE),SDS-PAGE, and combinations thereof. In some embodiments, evaluation ofproduct in accordance with the present invention may include a step ofevaluating appearance (either liquid or cake appearance).

Generally, formulations (lyophilized or aqueous) can be stored forextended periods of time at room temperature. Storage temperature maytypically range from 0° C. to 45° C. (e.g., 4° C., 20° C., 25° C., 45°C. etc.). Formulations may be stored for a period of months to a periodof years. Storage time generally will be 24 months, 12 months, 6 months,4.5 months, 3 months, 2 months or 1 month. Formulations can be storeddirectly in the container used for administration, eliminating transfersteps.

Formulations can be stored directly in the lyophilization container (iflyophilized), which may also function as the reconstitution vessel,eliminating transfer steps. Alternatively, lyophilized productformulations may be measured into smaller increments for storage.Storage should generally avoid circumstances that lead to degradation ofthe proteins, including but not limited to exposure to sunlight, UVradiation, other forms of electromagnetic radiation, excessive heat orcold, rapid thermal shock, and mechanical shock.

Lyophilization

Inventive methods in accordance with the present invention can beutilized to lyophilize any materials, in particular, therapeutic agents.Typically, a pre-lyophilization formulation further contains anappropriate choice of excipients or other components such asstabilizers, buffering agents, bulking agents, and surfactants toprevent compound of interest from degradation (e.g., proteinaggregation, deamidation, and/or oxidation) during freeze-drying andstorage. The formulation for lyophilization can include one or moreadditional ingredients including lyoprotectants or stabilizing agents,buffers, bulking agents, isotonicity agents and surfactants.

After the substance of interest and any additional components are mixedtogether, the formulation is lyophilized. Lyophilization generallyincludes three main stages: freezing, primary drying and secondarydrying. Freezing is necessary to convert water to ice or some amorphousformulation components to the crystalline form. Primary drying is theprocess step when ice is removed from the frozen product by directsublimation at low pressure and temperature. Secondary drying is theprocess step when bounded water is removed from the product matrixutilizing the diffusion of residual water to the evaporation surface.Product temperature during secondary drying is normally higher thanduring primary drying. See, Tang X. et al. (2004) “Design offreeze-drying processes for pharmaceuticals: Practical advice,” Pharm.Res., 21:191-200; Nail S. L. et al. (2002) “Fundamentals offreeze-drying,” in Development and manufacture of proteinpharmaceuticals. Nail S. L. editor New York: Kluwer Academic/PlenumPublishers, pp 281-353; Wang et al. (2000) “Lyophilization anddevelopment of solid protein pharmaceuticals,” Int. J. Pharm., 203:1-60;Williams N. A. et al. (1984) “The lyophilization of pharmaceuticals; Aliterature review.” J. Parenteral Sci. Technol., 38:48-59. Generally,any lyophilization process can be used in connection with the presentinvention.

In some embodiments, an annealing step may be introduced during theinitial freezing of the product. The annealing step may reduce theoverall cycle time. Without wishing to be bound by any theories, it iscontemplated that the annealing step can help promote excipientcrystallization and formation of larger ice crystals due tore-crystallization of small crystals formed during supercooling, which,in turn, improves reconstitution. Typically, an annealing step includesan interval or oscillation in the temperature during freezing. Forexample, the freeze temperature may be −40° C., and the annealing stepwill increase the temperature to, for example, −10° C. and maintain thistemperature for a set period of time. The annealing step time may rangefrom 0.5 hours to 8 hours (e.g., 0.5, 1.0 1.5, 2.0, 2.5, 3, 4, 6, and 8hours). The annealing temperature may be between the freezingtemperature and 0° C.

Lyophilization may be performed in a container, such as a tube, a bag, abottle, a tray, a vial (e.g., a glass vial), syringe or any othersuitable containers. The containers may be disposable. Lyophilizationmay also be performed in a large scale or small scale. In someinstances, it may be desirable to lyophilize the protein formulation inthe container in which reconstitution of the protein is to be carriedout in order to avoid a transfer step. The container in this instancemay, for example, be a 3, 4, 5, 10, 20, 50 or 100 cc vial.

Many different freeze-dryers are available for this purpose such as Hullpilot scale dryer (SP Industries, USA), Genesis (SP Industries)laboratory freeze-dryers, or any freeze-dryers capable of controllingthe given lyophilization process parameters. Freeze-drying isaccomplished by freezing the formulation and subsequently subliming icefrom the frozen content at a temperature suitable for primary drying.Initial freezing brings the formulation to a temperature below about−20° C. (e.g., −50° C., −45° C., −40° C., −35° C., −30° C., −25° C.,etc.) in typically not more than about 4 hours (e.g., not more thanabout 3 hours, not more than about 2.5 hours, not more than about 2hours). Under this condition, the product temperature is typically belowthe eutectic point or the collapse temperature of the formulation.Typically, the shelf temperature for the primary drying will range fromabout −30 to 25° C. (provided the product remains below the meltingpoint during primary drying) at a suitable pressure, ranging typicallyfrom about 20 to 250 mTorr. The formulation, size and type of thecontainer holding the sample (e.g., glass vial) and the volume of liquidwill mainly dictate the time required for drying, which can range from afew hours to several days. A secondary drying stage is carried out atabout 0-60° C., depending primarily on the type and size of containerand the type of therapeutic protein employed. Again, volume of liquidwill mainly dictate the time required for drying, which can range from afew hours to several days.

As a general proposition, lyophilization will result in a lyophilizedformulation in which the moisture content thereof is less than about 5%,less than about 4%, less than about 3%, less than about 2%, less thanabout 1%, and less than about 0.5%.

Reconsititution

While the pharmaceutical compositions of the present invention aregenerally in an aqueous form upon administration to a subject, in someembodiments the pharmaceutical compositions of the present invention arelyophilized. Such compositions must be reconstituted by adding one ormore diluents thereto prior to administration to a subject. At thedesired stage, typically at an appropriate time prior to administrationto the patient, the lyophilized formulation may be reconstituted with adiluent such that the protein concentration in the reconstitutedformulation is desirable.

Various diluents may be used in accordance with the present invention.In some embodiments, a suitable diluent for reconstitution is water. Thewater used as the diluent can be treated in a variety of ways includingreverse osmosis, distillation, deionization, filtrations (e.g.,activated carbon, microfiltration, nanofiltration) and combinations ofthese treatment methods. In general, the water should be suitable forinjection including, but not limited to, sterile water or bacteriostaticwater for injection.

Additional exemplary diluents include a pH buffered solution (e.g.,phosphate-buffered saline), sterile saline solution, Elliot's solution,Ringer's solution or dextrose solution. Suitable diluents may optionallycontain a preservative. Exemplary preservatives include aromaticalcohols such as benzyl or phenol alcohol. The amount of preservativeemployed is determined by assessing different preservativeconcentrations for compatibility with the protein and preservativeefficacy testing. For example, if the preservative is an aromaticalcohol (such as benzyl alcohol), it can be present in an amount fromabout 0.1-2.0%, from about 0.5-1.5%, or about 1.0-1.2%.

Diluents suitable for the invention may include a variety of additives,including, but not limited to, pH buffering agents, (e.g. Tris,histidine,) salts (e.g., sodium chloride) and other additives (e.g.,sucrose) including those described above (e.g. stabilizing agents,isotonicity agents).

According to the present invention, a lyophilized substance (e.g.,protein) can be reconstituted to a concentration of at least 25 mg/ml(e.g., at least 50 mg/ml, at least 75 mg/ml, at least 100 mg/) and inany ranges therebetween. In some embodiments, a lyophilized substance(e.g., protein) may be reconstituted to a concentration ranging fromabout 1 mg/ml to 100 mg/ml (e.g., from about 1 mg/ml to 50 mg/ml, from 1mg/ml to 100 mg/ml, from about 1 mg/ml to about 5 mg/ml, from about 1mg/ml to about 10 mg/ml, from about 1 mg/ml to about 25 mg/ml, fromabout 1 mg/ml to about 75 mg/ml, from about 10 mg/ml to about 30 mg/ml,from about 10 mg/ml to about 50 mg/ml, from about 10 mg/ml to about 75mg/ml, from about 10 mg/ml to about 100 mg/ml, from about 25 mg/ml toabout 50 mg/ml, from about 25 mg/ml to about 75 mg/ml, from about 25mg/ml to about 100 mg/ml, from about 50 mg/ml to about 75 mg/ml, fromabout 50 mg/ml to about 100 mg/ml). In some embodiments, theconcentration of protein in the reconstituted formulation may be higherthan the concentration in the pre-lyophilization formulation. Highprotein concentrations in the reconstituted formulation are consideredto be particularly useful where subcutaneous or intramuscular deliveryof the reconstituted formulation is intended. In some embodiments, theprotein concentration in the reconstituted formulation may be about 2-50times (e.g., about 2-20, about 2-10 times, or about 2-5 times) of thepre-lyophilized formulation. In some embodiments, the proteinconcentration in the reconstituted formulation may be at least about 2times (e.g., at least about 3, 4, 5, 10, 20, 40 times) of thepre-lyophilized formulation.

Reconstitution according to the present invention may be performed inany container. Exemplary containers suitable for the invention include,but are not limited to, such as tubes, vials, syringes (e.g.,single-chamber or dual-chamber), bags, bottles, and trays. Suitablecontainers may be made of any materials such as glass, plastics, metal.The containers may be disposable or reusable. Reconstitution may also beperformed in a large scale or small scale.

In some instances, it may be desirable to lyophilize the proteinformulation in the container in which reconstitution of the protein isto be carried out in order to avoid a transfer step. The container inthis instance may, for example, be a 3, 4, 5, 10, 20, 50 or 100 cc vial.In some embodiments, a suitable container for lyophilization andreconstitution is a dual chamber syringe (e.g., Lyo-Ject,® (Vetter)syringes). For example, a dual chamber syringe may contain both thelyophilized substance and the diluent, each in a separate chamber,separated by a stopper (see Example 5). To reconstitute, a plunger canbe attached to the stopper at the diluent side and pressed to movediluent into the product chamber so that the diluent can contact thelyophilized substance and reconstitution may take place as describedherein (see Example 5).

The pharmaceutical compositions, formulations and related methods of theinvention are useful for delivering a variety of therapeutic agents tothe CNS of a subject (e.g., intrathecally, intraventricularly orintracisternally) and for the treatment of the associated diseases. Thepharmaceutical compositions of the present invention are particularlyuseful for delivering proteins and enzymes (e.g., enzyme replacementtherapy) to subjects suffering from lysosomal storage disorders. Thelysosomal storage diseases represent a group of relatively rareinherited metabolic disorders that result from defects in lysosomalfunction. The lysosomal diseases are characterized by the accumulationof undigested macromolecules within the lysosomes, which results in anincrease in the size and number of such lysosomes and ultimately incellular dysfunction and clinical abnormalities.

CNS Delivery

It is contemplated that various stable formulations described herein aregenerally suitable for CNS delivery of therapeutic agents. Stableformulations according to the present invention can be used for CNSdelivery via various techniques and routes including, but not limitedto, intraparenchymal, intracerebral, intravetricular cerebral (ICV),intrathecal (e.g., IT-Lumbar, IT-cisterna magna) administrations and anyother techniques and routes for injection directly or indirectly to theCNS and/or CSF.

Intrathecal Delivery

In some embodiments, a replacement enzyme is delivered to the CNS in aformulation described herein. In some embodiments, a replacement enzymeis delivered to the CNS by administering into the cerebrospinal fluid(CSF) of a subject in need of treatment. In some embodiments,intrathecal administration is used to deliver a desired replacementenzyme (e.g., an I2S protein) into the CSF. As used herein, intrathecaladministration (also referred to as intrathecal injection) refers to aninjection into the spinal canal (intrathecal space surrounding thespinal cord). Various techniques may be used including, withoutlimitation, lateral cerebroventricular injection through a burrhole orcistemal or lumbar puncture or the like. Exemplary methods are describedin Lazorthes et al. Advances in Drug Delivery Systems and Applicationsin Neurosurgery, 143-192 and Omaya et al., Cancer Drug Delivery, 1:169-179, the contents of which are incorporated herein by reference.

According to the present invention, an enzyme may be injected at anyregion surrounding the spinal canal. In some embodiments, an enzyme isinjected into the lumbar area or the cisterna magna orintraventricularly into a cerebral ventricle space. As used herein, theterm “lumbar region” or “lumbar area” refers to the area between thethird and fourth lumbar (lower back) vertebrae and, more inclusively,the L2-S1 region of the spine. Typically, intrathecal injection via thelumbar region or lumber area is also referred to as “lumbar IT delivery”or “lumbar IT administration.” The term “cisterna magna” refers to thespace around and below the cerebellum via the opening between the skulland the top of the spine. Typically, intrathecal injection via cisternamagna is also referred to as “cisterna magna delivery.” The term“cerebral ventricle” refers to the cavities in the brain that arecontinuous with the central canal of the spinal cord. Typically,injections via the cerebral ventricle cavities are referred to asintravetricular Cerebral (ICV) delivery.

In some embodiments, “intrathecal administration” or “intrathecaldelivery” according to the present invention refers to lumbar ITadministration or delivery, for example, delivered between the third andfourth lumbar (lower back) vertebrae and, more inclusively, the L2-S1region of the spine. It is contemplated that lumbar IT administration ordelivery distinguishes over cisterna magna delivery in that lumbar ITadministration or delivery according to our invention provides betterand more effective delivery to the distal spinal canal, while cisternamagna delivery, among other things, typically does not deliver well tothe distal spinal canal.

Device for Intrathecal Delivery

Various devices may be used for intrathecal delivery according to thepresent invention. In some embodiments, a device for intrathecaladministration contains a fluid access port (e.g., injectable port); ahollow body (e.g., catheter) having a first flow orifice in fluidcommunication with the fluid access port and a second flow orificeconfigured for insertion into spinal cord; and a securing mechanism forsecuring the insertion of the hollow body in the spinal cord. As anon-limiting example shown in FIG. 62, a suitable securing mechanismcontains one or more nobs mounted on the surface of the hollow body anda sutured ring adjustable over the one or more nobs to prevent thehollow body (e.g., catheter) from slipping out of the spinal cord. Invarious embodiments, the fluid access port comprises a reservoir. Insome embodiments, the fluid access port comprises a mechanical pump(e.g., an infusion pump). In some embodiments, an implanted catheter isconnected to either a reservoir (e.g., for bolus delivery), or aninfusion pump. The fluid access port may be implanted or external

In some embodiments, intrathecal administration may be performed byeither lumbar puncture (i.e., slow bolus) or via a port-catheterdelivery system (i.e., infusion or bolus). In some embodiments, thecatheter is inserted between the laminae of the lumbar vertebrae and thetip is threaded up the thecal space to the desired level (generallyL3-L4) (FIG. 63).

Relative to intravenous administration, a single dose volume suitablefor intrathecal administration is typically small. Typically,intrathecal delivery according to the present invention maintains thebalance of the composition of the CSF as well as the intracranialpressure of the subject. In some embodiments, intrathecal delivery isperformed absent the corresponding removal of CSF from a subject. Insome embodiments, a suitable single dose volume may be e.g., less thanabout 10 ml, 8 ml, 6 ml, 5 ml, 4 ml, 3 ml, 2 ml, 1.5 ml, 1 ml, or 0.5ml. In some embodiments, a suitable single dose volume may be about0.5-5 ml, 0.5-4 ml, 0.5-3 ml, 0.5-2 ml, 0.5-1 ml, 1-3 ml, 1-5 ml, 1.5-3ml, 1-4 ml, or 0.5-1.5 ml. In some embodiments, intrathecal deliveryaccording to the present invention involves a step of removing a desiredamount of CSF first. In some embodiments, less than about 10 ml (e.g.,less than about 9 ml, 8 ml, 7 ml, 6 ml, 5 ml, 4 ml, 3 ml, 2 ml, 1 ml) ofCSF is first removed before IT administration. In those cases, asuitable single dose volume may be e.g., more than about 3 ml, 4 ml, 5ml, 6 ml, 7 ml, 8 ml, 9 ml, 10 ml, 15 ml, or 20 ml.

Various other devices may be used to effect intrathecal administrationof a therapeutic composition. For example, formulations containingdesired enzymes may be given using an Ommaya reservoir which is incommon use for intrathecally administering drugs for meningealcarcinomatosis (Lancet 2: 983-84, 1963). More specifically, in thismethod, a ventricular tube is inserted through a hole formed in theanterior horn and is connected to an Ommaya reservoir installed underthe scalp, and the reservoir is subcutaneously punctured tointrathecally deliver the particular enzyme being replaced, which isinjected into the reservoir. Other devices for intrathecaladministration of therapeutic compositions or formulations to anindividual are described in U.S. Pat. No. 6,217,552, incorporated hereinby reference. Alternatively, the drug may be intrathecally given, forexample, by a single injection, or continuous infusion. It should beunderstood that the dosage treatment may be in the form of a single doseadministration or multiple doses.

For injection, formulations of the invention can be formulated in liquidsolutions. In addition, the enzyme may be formulated in solid form andre-dissolved or suspended immediately prior to use. Lyophilized formsare also included. The injection can be, for example, in the form of abolus injection or continuous infusion (e.g., using infusion pumps) ofthe enzyme.

In one embodiment of the invention, the enzyme is administered bylateral cerebro ventricular injection into the brain of a subject. Theinjection can be made, for example, through a burr hole made in thesubject's skull. In another embodiment, the enzyme and/or otherpharmaceutical formulation is administered through a surgically insertedshunt into the cerebral ventricle of a subject. For example, theinjection can be made into the lateral ventricles, which are larger. Insome embodiments, injection into the third and fourth smaller ventriclescan also be made.

In yet another embodiment, the pharmaceutical compositions used in thepresent invention are administered by injection into the cisterna magna,or lumbar area of a subject.

In another embodiment of the method of the invention, thepharmaceutically acceptable formulation provides sustained delivery,e.g., “slow release” of the enzyme or other pharmaceutical compositionused in the present invention, to a subject for at least one, two,three, four weeks or longer periods of time after the pharmaceuticallyacceptable formulation is administered to the subject.

As used herein, the term “sustained delivery” refers to continualdelivery of a pharmaceutical formulation of the invention in vivo over aperiod of time following administration, preferably at least severaldays, a week or several weeks. Sustained delivery of the composition canbe demonstrated by, for example, the continued therapeutic effect of theenzyme over time (e.g., sustained delivery of the enzyme can bedemonstrated by continued reduced amount of storage granules in thesubject). Alternatively, sustained delivery of the enzyme may bedemonstrated by detecting the presence of the enzyme in vivo over time.

Delivery to Target Tissues

As discussed above, one of the surprising and important features of thepresent invention is that therapeutic agents, in particular, replacementenzymes administered using inventive methods and compositions of thepresent invention are able to effectively and extensively diffuse acrossthe brain surface and penetrate various layers or regions of the brain,including deep brain regions. In addition, inventive methods andcompositions of the present invention effectively deliver therapeuticagents (e.g., an I2S enzyme) to various tissues, neurons or cells ofspinal cord, including the lumbar region, which is hard to target byexisting CNS delivery methods such as ICV injection. Furthermore,inventive methods and compositions of the present invention deliversufficient amount of therapeutic agents (e.g., an 12S enzyme) to theblood stream and various peripheral organs and tissues.

Thus, in some embodiments, a therapeutic protein (e.g., an I2S enzyme)is delivered to the central nervous system of a subject. In someembodiments, a therapeutic protein (e.g., an I2S enzyme) is delivered toone or more of target tissues of brain, spinal cord, and/or peripheralorgans. As used herein, the term “target tissues” refers to any tissuethat is affected by the lysosomal storage disease to be treated or anytissue in which the deficient lysosomal enzyme is normally expressed. Insome embodiments, target tissues include those tissues in which there isa detectable or abnormally high amount of enzyme substrate, for examplestored in the cellular lysosomes of the tissue, in patients sufferingfrom or susceptible to the lysosomal storage disease. In someembodiments, target tissues include those tissues that displaydisease-associated pathology, symptom, or feature. In some embodiments,target tissues include those tissues in which the deficient lysosomalenzyme is normally expressed at an elevated level. As used herein, atarget tissue may be a brain target tissue, a spinal cord target tissueand/or a peripheral target tissue. Exemplary target tissues aredescribed in detail below.

Brain Target Tissues

In general, the brain can be divided into different regions, layers andtissues. For example, meningeal tissue is a system of membranes whichenvelops the central nervous system, including the brain. The meningescontain three layers, including dura matter, arachnoid matter, and piamatter. In general, the primary function of the meninges and of thecerebrospinal fluid is to protect the central nervous system. In someembodiments, a therapeutic protein in accordance with the presentinvention is delivered to one or more layers of the meninges.

The brain has three primary subdivisions, including the cerebrum,cerebellum, and brain stem. The cerebral hemispheres, which are situatedabove most other brain structures, are covered with a cortical layer.Underneath the cerebrum lies the brainstem, which resembles a stalk onwhich the cerebrum is attached. At the rear of the brain, beneath thecerebrum and behind the brainstem, is the cerebellum.

The diencephalon, which is located near the midline of the brain andabove the mesencephalon, contains the thalamus, metathalamus,hypothalamus, epithalamus, prethalamus, and pretectum. Themesencephalon, also called the midbrain, contains the tectum,tegumentum, ventricular mesocoelia, and cerebral peduncels, the rednucleus, and the cranial nerve III nucleus. The mesencephalon isassociated with vision, hearing, motor control, sleep/wake, alertness,and temperature regulation.

Regions of tissues of the central nervous system, including the brain,can be characterized based on the depth of the tissues. For example, CNS(e.g., brain) tissues can be characterized as surface or shallowtissues, mid-depth tissues, and/or deep tissues.

According to the present invention, a therapeutic protein (e.g., areplacement enzyme) may be delivered to any appropriate brain targettissue(s) associated with a particular disease to be treated in asubject. In some embodiments, a therapeutic protein (e.g., a replacementenzyme) in accordance with the present invention is delivered to surfaceor shallow brain target tissue. In some embodiments, a therapeuticprotein in accordance with the present invention is delivered tomid-depth brain target tissue. In some embodiments, a therapeuticprotein in accordance with the present invention is delivered to deepbrain target tissue. In some embodiments, a therapeutic protein inaccordance with the present invention is delivered to a combination ofsurface or shallow brain target tissue, mid-depth brain target tissue,and/or deep brain target tissue. In some embodiments, a therapeuticprotein in accordance with the present invention is delivered to a deepbrain tissue at least 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or morebelow (or internal to) the external surface of the brain.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toone or more surface or shallow tissues of cerebrum. In some embodiments,the targeted surface or shallow tissues of the cerebrum are locatedwithin 4 mm from the surface of the cerebrum. In some embodiments, thetargeted surface or shallow tissues of the cerebrum are selected frompia mater tissues, cerebral cortical ribbon tissues, hippocampus,Virchow Robin space, blood vessels within the VR space, the hippocampus,portions of the hypothalamus on the inferior surface of the brain, theoptic nerves and tracts, the olfactory bulb and projections, andcombinations thereof.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toone or more deep tissues of the cerebrum. In some embodiments, thetargeted surface or shallow tissues of the cerebrum are located 4 mm(e.g., 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm) below (or internal to)the surface of the cerebrum. In some embodiments, targeted deep tissuesof the cerebrum include the cerebral cortical ribbon. In someembodiments, targeted deep tissues of the cerebrum include one or moreof the diencephalon (e.g., the hypothalamus, thalamus, prethalamus,subthalamus, etc.), metencephalon, lentiform nuclei, the basal ganglia,caudate, putamen, amygdala, globus pallidus, and combinations thereof.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toone or more tissues of the cerebellum. In certain embodiments, thetargeted one or more tissues of the cerebellum are selected from thegroup consisting of tissues of the molecular layer, tissues of thePurkinje cell layer, tissues of the Granular cell layer, cerebellarpeduncles, and combination thereof. In some embodiments, therapeuticagents (e.g., enzymes) are delivered to one or more deep tissues of thecerebellum including, but not limited to, tissues of the Purkinje celllayer, tissues of the Granular cell layer, deep cerebellar white mattertissue (e.g., deep relative to the Granular cell layer), and deepcerebellar nuclei tissue.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toone or more tissues of the brainstem. In some embodiments, the targetedone or more tissues of the brainstem include brain stem white mattertissue and/or brain stem nuclei tissue.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered tovarious brain tissues including, but not limited to, gray matter, whitematter, periventricular areas, pia-arachnoid, meninges, neocortex,cerebellum, deep tissues in cerebral cortex, molecular layer,caudate/putamen region, midbrain, deep regions of the pons or medulla,and combinations thereof.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered tovarious cells in the brain including, but not limited to, neurons, glialcells, perivascular cells and/or meningeal cells. In some embodiments, atherapeutic protein is delivered to oligodendrocytes of deep whitematter.

Spinal Cord

In general, regions or tissues of the spinal cord can be characterizedbased on the depth of the tissues. For example, spinal cord tissues canbe characterized as surface or shallow tissues, mid-depth tissues,and/or deep tissues.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toone or more surface or shallow tissues of the spinal cord. In someembodiments, a targeted surface or shallow tissue of the spinal cord islocated within 4 mm from the surface of the spinal cord. In someembodiments, a targeted surface or shallow tissue of the spinal cordcontains pia matter and/or the tracts of white matter.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toone or more deep tissues of the spinal cord. In some embodiments, atargeted deep tissue of the spinal cord is located internal to 4 mm fromthe surface of the spinal cord. In some embodiments, a targeted deeptissue of the spinal cord contains spinal cord grey matter and/orependymal cells.

In some embodiments, therapeutic agents (e.g., enzymes) are delivered toneurons of the spinal cord.

Peripheral Target Tissues

As used herein, peripheral organs or tissues refer to any organs ortissues that are not part of the central nervous system (CNS).Peripheral target tissues may include, but are not limited to, bloodsystem, liver, kidney, heart, endothelium, bone marrow and bone marrowderived cells, spleen, lung, lymph node, bone, cartilage, ovary andtestis. In some embodiments, a therapeutic protein (e.g., a replacementenzyme) in accordance with the present invention is delivered to one ormore of the peripheral target tissues.

Biodistribution and Bioavailability

In various embodiments, once delivered to the target tissue, atherapeutic agent (e.g., an 12S enzyme) is localized intracellularly.For example, a therapeutic agent (e.g., enzyme) may be localized toexons, axons, lysosomes, mitochondria or vacuoles of a target cell(e.g., neurons such as Purkinje cells). For example, in some embodimentsintrathecally-administered enzymes demonstrate translocation dynamicssuch that the enzyme moves within the perivascular space (e.g., bypulsation-assisted convective mechanisms). In addition, active axonaltransport mechanisms relating to the association of the administeredprotein or enzyme with neurofilaments may also contribute to orotherwise facilitate the distribution of intrathecally-administeredproteins or enzymes into the deeper tissues of the central nervoussystem.

In some embodiments, a therapeutic agent (e.g., an I2S enzyme) deliveredaccording to the present invention may achieve therapeutically orclinically effective levels or activities in various targets tissuesdescribed herein. As used herein, a therapeutically or clinicallyeffective level or activity is a level or activity sufficient to confera therapeutic effect in a target tissue. The therapeutic effect may beobjective (i.e., measurable by some test or marker) or subjective (i.e.,subject gives an indication of or feels an effect). For example, atherapeutically or clinically effective level or activity may be anenzymatic level or activity that is sufficient to ameliorate symptomsassociated with the disease in the target tissue (e.g., GAG storage).

In some embodiments, a therapeutic agent (e.g., a replacement enzyme)delivered according to the present invention may achieve an enzymaticlevel or activity that is at least 5%, 10%, 20%, 30%, 40%, 50%, 60%,70%, 80%, 90%, 95% of the normal level or activity of the correspondinglysosomal enzyme in the target tissue. In some embodiments, atherapeutic agent (e.g., a replacement enzyme) delivered according tothe present invention may achieve an enzymatic level or activity that isincreased by at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold,7-fold, 8-fold, 9-fold or 10-fold as compared to a control (e.g.,endogenous levels or activities without the treatment). In someembodiments, a therapeutic agent (e.g., a replacement enzyme) deliveredaccording to the present invention may achieve an increased enzymaticlevel or activity at least approximately 10 nmol/hr/mg, 20 nmol/hr/mg,40 nmol/hr/mg, 50 nmol/hr/mg, 60 nmol/hr/mg, 70 nmol/hr/mg, 80nmol/hr/mg, 90 nmol/hr/mg, 100 nmol/hr/mg, 150 nmol/hr/mg, 200nmol/hr/mg, 250 nmol/hr/mg, 300 nmol/hr/mg, 350 nmol/hr/mg, 400nmol/hr/mg, 450 nmol/hr/mg, 500 nmol/hr/mg, 550 nmol/hr/mg or 600nmol/hr/mg in a target tissue.

In some embodiments, inventive methods according to the presentinvention are particularly useful for targeting the lumbar region. Insome embodiments, a therapeutic agent (e.g., a replacement enzyme)delivered according to the present invention may achieve an increasedenzymatic level or activity in the lumbar region of at leastapproximately 500 nmol/hr/mg, 600 nmol/hr/mg, 700 nmol/hr/mg, 800nmol/hr/mg, 900 nmol/hr/mg, 1000 nmol/hr/mg, 1500 nmol/hr/mg, 2000nmol/hr/mg, 3000 nmol/hr/mg, 4000 nmol/hr/mg, 5000 nmol/hr/mg, 6000nmol/hr/mg, 7000 nmol/hr/mg, 8000 nmol/hr/mg, 9000 nmol/hr/mg, or 10,000nmol/hr/mg.

In general, therapeutic agents (e.g., replacement enzymes) deliveredaccording to the present invention have sufficiently long half time inCSF and target tissues of the brain, spinal cord, and peripheral organs.In some embodiments, a therapeutic agent (e.g., a replacement enzyme)delivered according to the present invention may have a half-life of atleast approximately 30 minutes, 45 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10hours, 12 hours, 16 hours, 18 hours, 20 hours, 25 hours, 30 hours, 35hours, 40 hours, up to 3 days, up to 7 days, up to 14 days, up to 21days or up to a month. In some embodiments, In some embodiments, atherapeutic agent (e.g., a replacement enzyme) delivered according tothe present invention may retain detectable level or activity in CSF orbloodstream after 12 hours, 24 hours, 30 hours, 36 hours, 42 hours, 48hours, 54 hours, 60 hours, 66 hours, 72 hours, 78 hours, 84 hours, 90hours, 96 hours, 102 hours, or a week following administration.Detectable level or activity may be determined using various methodsknown in the art.

In certain embodiments, a therapeutic agent (e.g., a replacement enzyme)delivered according to the present invention achieves a concentration ofat least 30 μg/ml in the CNS tissues and cells of the subject followingadministration (e.g., one week, 3 days, 48 hours, 36 hours, 24 hours, 18hours, 12 hours, 8 hours, 6 hours, 4 hours, 3 hours, 2 hours, 1 hour, 30minutes, or less, following intrathecal administration of thepharmaceutical composition to the subject). In certain embodiments, atherapeutic agent (e.g., a replacement enzyme) delivered according tothe present invention achieves a concentration of at least 20 μg/ml, atleast 15 μg/ml, at least 10 μg/ml, at least 7.5 μg/ml, at least 5 μg/ml,at least 2.5 μg/ml, at least 1.0 μg/ml or at least 0.5 μg/ml in thetargeted tissues or cells of the subject (e.g., brain tissues orneurons) following administration to such subject (e.g., one week, 3days, 48 hours, 36 hours, 24 hours, 18 hours, 12 hours, 8 hours, 6hours, 4 hours, 3 hours, 2 hours, 1 hour, 30 minutes, or less followingintrathecal administration of such pharmaceutical compositions to thesubject).

Treatment of Hunter Syndrome and Other Lysosomal Storage Diseases

The lysosomal storage diseases represent a group of relatively rareinherited metabolic disorders that result from defects in lysosomalfunction. The lysosomal diseases are characterized by the accumulationof undigested macromolecules, including those enzyme substrates, withinthe lysosomes (see Table 1), which results in an increase in the sizeand number of such lysosomes and ultimately in cellular dysfunction andclinical abnormalities.

Inventive methods described herein can advantageously facilitate thedelivery of one or more therapeutic agents (e.g., one or morereplacement enzymes) to targeted organelles. For example, becauselysosomal storage disorders such as Hunter syndrome are characterized byan accumulation of glycosaminoglycans (GAG) in the lysosomes of affectedcells, the lysosomes represent a desired target organelle for thetreatment of the lysosomal storage disorders.

Inventive methods and compositions of the present invention areparticularly useful for treating those diseases having a CNS etiology orcomponent. Lysosomal storage diseases having a CNS etiology orcomponent, include for example and without limitation Sanfilipposyndrome Type A, Sanfilippo syndrome type B, Hunter syndrome,metachromatic leukodystrophy and globoid cell leukodystrophy. Prior tothe present invention, traditional therapies are limited in that theyare administered to subjects intravenously, and are generally onlyeffective in treating the somatic symptoms of the underlying enzymedeficiency. The compositions and methods of the present invention mayadvantageously be administered directly into the CNS of a subjectsuffering from a disease having such a CNS etiology thereby achieving atherapeutic concentration within the affected cells and tissues of theCNS (e.g., the brain), thus overcoming the limitations associated withtraditional systemic administration of such therapeutic agents.

In some embodiments, inventive methods and compositions of the inventionare useful for treating both the neurologic and the somatic sequelae orsymptoms of lysosomal storage disorders. For example, some embodimentsof the invention relate to compositions and methods of delivering one ormore therapeutic agents to the CNS of a subject (e.g., intrathecally,intraventricularly or intracisternally) for the treatment of the CNS orneurologic sequelae and manifestations of a lysosomal storage disease,while also treating the systemic or somatic manifestations of thatlysosomal storage disease. For example, some compositions of the presentinvention may be administered to a subject intrathecally, therebydelivering one or more therapeutic agents to the CNS of the subject andtreating the neurological sequelae, coupled with the intravenousadministration of one or more therapeutic agents to deliver suchtherapeutic agents to both the cells and tissues of the systemiccirculation (e.g., cells and tissues of heart, lungs, liver, kidney orlymph nodes) to thereby treat the somatic sequelae. For example, asubject having or otherwise affected by a lysosomal storage disease(e.g., Hunter syndrome) may be administered a pharmaceutical compositioncomprising one or more therapeutic agents (e.g., iduronate-2-sulfatase)intrathecally at least once per week, biweekly, monthly, bimonthly ormore to treat the neurologic sequelae, while a different therapeuticagent is administered to the subject intravenously on a more frequentbasis (e.g., once per day, every other day, three times a week orweekly) to treat the systemic or somatic manifestations of the disease.

Hunter syndrome, or Mucopolysaccharidosis II (MPS II), is an X-linkedheritable metabolic disorder resulting from a deficiency of the enzymeiduronate-2-sulfatase (I2S). I2S is localized to lysosomes and plays animportant role in the catabolism of glycosaminoglycans (GAGs) heparan-and dermatan-sulfate. In the absence of enzyme, these substratesaccumulate within cells, ultimately causing engorgement, followed bycellular death and tissue destruction. Due to the widespread expressionof enzyme, multiple cell types and organ systems are affected in MPS IIpatients.

A defining clinical feature of this disorder is central nervous system(CNS) degeneration, which results in cognitive impairment (e.g.,decrease in IQ). Additionally, MRI scans of affected individuals haverevealed white matter lesions, dilated perivascular spaces in the brainparenchyma, ganglia, corpus callosum, and brainstem; atrophy; andventriculomegaly (Wang et al. Molecular Genetics and Metabolism, 2009).The disease typically manifests itself in the first years of life withorganomegaly and skeletal abnormalities. Some affected individualsexperience a progressive loss of cognitive function, with most affectedindividuals dying of disease-associated complications in their first orsecond decade.

Compositions and methods of the present invention may be used toeffectively treat individuals suffering from or susceptible to HunterSyndrome. The terms, “treat” or “treatment,” as used herein, refers toamelioration of one or more symptoms associated with the disease,prevention or delay of the onset of one or more symptoms of the disease,and/or lessening of the severity or frequency of one or more symptoms ofthe disease.

In some embodiments, treatment refers to partially or completealleviation, amelioration, relief, inhibition, delaying onset, reducingseverity and/or incidence of neurological impairment in a HunterSyndrome patient. As used herein, the term “neurological impairment”includes various symptoms associated with impairment of the centralnervous system (e.g., the brain and spinal cord). Symptoms ofneurological impairment may include, for example, e.g., cognitiveimpairment; white matter lesions; dilated perivascular spaces in thebrain parenchyma, ganglia, corpus callosum, and/or brainstem; atrophy;and/or ventriculomegaly, among others.

In some embodiments, treatment refers to decreased lysosomal storage(e.g., of GAG) in various tissues. In some embodiments, treatment refersto decreased lysosomal storage in brain target tissues, spinal cordneurons, and/or peripheral target tissues. In certain embodiments,lysosomal storage is decreased by about 5%, 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% ormore as compared to a control. In some embodiments, lysosomal storage isdecreased by at least 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold,7-fold, 8-fold, 9-fold or 10-fold as compared to a control. In someembodiments, lysosomal storage is measured by the presence of lysosomalstorage granules (e.g., zebra-striped morphology). The presence oflysosomal storage granules can be measured by various means known in theart, such as by histological analysis.

In some embodiments, treatment refers to reduced vacuolization inneurons (e.g., neurons containing Purkinje cells). In certainembodiments, vacuolization in neurons is decreased by about 5%, 10%,15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%,85%, 90%, 95%, 100% or more as compared to a control. In someembodiments, vacuolization is decreased by at least 1-fold, 2-fold,3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold or 10-fold ascompared to a control. The presence of and reduction of vacuolizationcan be measured by various means known in the art, such as byhistological analysis

In some embodiments, treatment refers to increased I2S enzyme activityin various tissues. In some embodiments, treatment refers to increasedI2S enzyme activity in brain target tissues, spinal cord neurons and/orperipheral target tissues. In some embodiments, I2S enzyme activity isincreased by about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, 500%,600%, 700%, 800%, 900% 1000% or more as compared to a control. In someembodiments, I2S enzyme activity is increased by at least 1-fold,2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold or10-fold as compared to a control. In some embodiments, increased I2Senzymatic activity is at least approximately 10 nmol/hr/mg, 20nmol/hr/mg, 40 nmol/hr/mg, 50 nmol/hr/mg, 60 nmol/hr/mg, 70 nmol/hr/mg,80 nmol/hr/mg, 90 nmol/hr/mg, 100 nmol/hr/mg, 150 nmol/hr/mg, 200nmol/hr/mg, 250 nmol/hr/mg, 300 nmol/hr/mg, 350 nmol/hr/mg, 400nmol/hr/mg, 450 nmol/hr/mg, 500 nmol/hr/mg, 550 nmol/hr/mg, 600nmol/hr/mg or more. In some embodiments, I2S enzymatic activity isincreased in the lumbar region or in cells in the lumbar region. In someembodiments, increased I2S enzymatic activity in the lumbar region is atleast approximately 2000 nmol/hr/mg, 3000 nmol/hr/mg, 4000 nmol/hr/mg,5000 nmol/hr/mg, 6000 nmol/hr/mg, 7000 nmol/hr/mg, 8000 nmol/hr/mg, 9000nmol/hr/mg, 10,000 nmol/hr/mg, or more. In some embodiments, I2Senzymatic activity is increased in the distal spinal cord or in cells ofthe distal spinal cord.

In some embodiments, treatment refers to decreased progression of lossof cognitive ability. In certain embodiments, progression of loss ofcognitive ability is decreased by about 5%, 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% ormore as compared to a control. In some embodiments, treatment refers todecreased developmental delay. In certain embodiments, developmentaldelay is decreased by about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%,50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% or more ascompared to a control.

In some embodiments, treatment refers to increased survival (e.g.survival time). For example, treatment can result in an increased lifeexpectancy of a patient. In some embodiments, treatment according to thepresent invention results in an increased life expectancy of a patientby more than about 5%, about 10%, about 15%, about 20%, about 25%, about30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%,about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about95%, about 100%, about 105%, about 110%, about 115%, about 120%, about125%, about 130%, about 135%, about 140%, about 145%, about 150%, about155%, about 160%, about 165%, about 170%, about 175%, about 180%, about185%, about 190%, about 195%, about 200% or more, as compared to theaverage life expectancy of one or more control individuals with similardisease without treatment. In some embodiments, treatment according tothe present invention results in an increased life expectancy of apatient by more than about 6 month, about 7 months, about 8 months,about 9 months, about 10 months, about 11 months, about 12 months, about2 years, about 3 years, about 4 years, about 5 years, about 6 years,about 7 years, about 8 years, about 9 years, about 10 years or more, ascompared to the average life expectancy of one or more controlindividuals with similar disease without treatment. In some embodiments,treatment according to the present invention results in long termsurvival of a patient. As used herein, the term “long term survival”refers to a survival time or life expectancy longer than about 40 years,45 years, 50 years, 55 years, 60 years, or longer.

The terms, “improve,” “increase” or “reduce,” as used herein, indicatevalues that are relative to a control. In some embodiments, a suitablecontrol is a baseline measurement, such as a measurement in the sameindividual prior to initiation of the treatment described herein, or ameasurement in a control individual (or multiple control individuals) inthe absence of the treatment described herein. A “control individual” isan individual afflicted with Hunter Syndrome, who is about the same ageand/or gender as the individual being treated (to ensure that the stagesof the disease in the treated individual and the control individual(s)are comparable).

The individual (also referred to as “patient” or “subject”) beingtreated is an individual (fetus, infant, child, adolescent, or adulthuman) having Hunter Syndrome or having the potential to develop HunterSyndrome. The individual can have residual endogenous I2S expressionand/or activity, or no measurable activity. For example, the individualhaving Hunter Syndrome may have I2S expression levels that are less thanabout 30-50%, less than about 25-30%, less than about 20-25%, less thanabout 15-20%, less than about 10-15%, less than about 5-10%, less thanabout 0.1-5% of normal I2S expression levels.

In some embodiments, the individual is an individual who has beenrecently diagnosed with the disease. Typically, early treatment(treatment commencing as soon as possible after diagnosis) is importantto minimize the effects of the disease and to maximize the benefits oftreatment.

Immune Tolerance

Generally, intrathecal administration of a therapeutic agent (e.g., areplacement enzyme) according to the present invention does not resultin severe adverse effects in the subject. As used herein, severe adverseeffects induce, but are not limited to, substantial immune response,toxicity, or death. As used herein, the term “substantial immuneresponse” refers to severe or serious immune responses, such as adaptiveT-cell immune responses.

Thus, in many embodiments, inventive methods according to the presentinvention do not involve concurrent immunosuppressant therapy (i.e., anyimmunosuppressant therapy used as pre-treatment/pre-conditioning or inparallel to the method). In some embodiments, inventive methodsaccording to the present invention do not involve an immune toleranceinduction in the subject being treated. In some embodiments, inventivemethods according to the present invention do not involve apre-treatment or preconditioning of the subject using T-cellimmunosuppressive agent.

In some embodiments, intrathecal administration of therapeutic agentscan mount an immune response against these agents. Thus, in someembodimnets, it may be useful to render the subject receiving thereplacement enzyme tolerant to the enzyme replacement therapy. Immunetolerance may be induced using various methods known in the art. Forexample, an initial 30-60 day regimen of a T-cell immunosuppressiveagent such as cyclosporin A (CsA) and an antiproliferative agent, suchas, azathioprine (Aza), combined with weekly intrathecal infusions oflow doses of a desired replacement enzyme may be used.

Any immunosuppressant agent known to the skilled artisan may be employedtogether with a combination therapy of the invention. Suchimmunosuppressant agents include but are not limited to cyclosporine,FK506, rapamycin, CTLA4-Ig, and anti-TNF agents such as etanercept (seee.g. Moder, 2000, Ann. Allergy Asthma Immunol. 84, 280-284; Nevins,2000, Curr. Opin. Pediatr. 12, 146-150; Kurlberg et al., 2000, Scand. J.Immunol. 51, 224-230; Ideguchi et al., 2000, Neuroscience 95, 217-226;Potter et al., 1999, Ann. N.Y. Acad. Sci. 875, 159-174; Slavik et al.,1999, Immunol. Res. 19, 1-24; Gaziev et al., 1999, Bone MarrowTransplant. 25, 689-696; Henry, 1999, Clin. Transplant. 13, 209-220;Gummert et al., 1999, J. Am. Soc. Nephrol. 10, 1366-1380; Qi et al.,2000, Transplantation 69, 1275-1283). The anti-IL2 receptor(.alpha.-subunit) antibody daclizumab (e.g. Zenapax™), which has beendemonstrated effective in transplant patients, can also be used as animmunosuppressant agent (see e.g. Wiseman et al., 1999, Drugs 58,1029-1042; Beniaminovitz et al., 2000, N. Engl J. Med. 342, 613-619;Ponticelli et al., 1999, Drugs R. D. 1, 55-60; Berard et al., 1999,Pharmacotherapy 19, 1127-1137; Eckhoff et al., 2000, Transplantation 69,1867-1872; Ekberg et al., 2000, Transpl. Int. 13, 151-159).Additionalimmunosuppressant agents include but are not limited toanti-CD2 (Branco et al., 1999, Transplantation 68, 1588-1596; Przepiorkaet al., 1998, Blood 92, 4066-4071), anti-CD4 (Marinova-Mutafchieva etal., 2000, Arthritis Rheum. 43, 638-644; Fishwild et al., 1999, Clin.Immunol. 92, 138-152), and anti-CD40 ligand (Hong et al., 2000, Semin.Nephrol. 20, 108-125; Chirmule et al., 2000, J. Virol. 74, 3345-3352;Ito et al., 2000, J. Immunol. 164, 1230-1235).

Administration

Inventive methods of the present invention contemplate single as well asmultiple administrations of a therapeutically effective amount of thetherapeutic agents (e.g., replacement enzymes) described herein.Therapeutic agents (e.g., replacement enzymes) can be administered atregular intervals, depending on the nature, severity and extent of thesubject's condition (e.g., a lysosomal storage disease). In someembodiments, a therapeutically effective amount of the therapeuticagents (e.g., replacement enzymes) of the present invention may beadministered intrathecally periodically at regular intervals (e.g., onceevery year, once every six months, once every five months, once everythree months, bimonthly (once every two months), monthly (once everymonth), biweekly (once every two weeks), weekly, daily or continuously).

In some embodiments, intrathecal administration may be used inconjunction with other routes of administration (e.g., intravenous,subcutaneously, intramuscularly, parenterally, transdermally, ortransmucosally (e.g., orally or nasally)). In some embodiments, thoseother routes of administration (e.g., intravenous administration) may beperformed no more frequent than biweekly, monthly, once every twomonths, once every three months, once every four months, once every fivemonths, once every six months, annually administration. In someembodiments, the method further comprises administering the I2Sreplacement enzyme intravenously to the subject. In certain embodiments,the intravenous administration is no more frequent than weeklyadministration (e.g., no more frequent than biweekly, monthly, onceevery two months, once every three months, once every four months, onceevery five months, or once every six months). In certain embodiments,the intravenous administration is more frequent than monthlyadministration, such as twice weekly, weekly, every other week, or twicemonthly. In some embodiments, intravenous and intrathecaladministrations are performed on the same day. In some embodiments, theintravenous and intrathecal administrations are not performed within acertain amount of time of each other, such as not within at least 2days, within at least 3 days, within at least 4 days, within at least 5days, within at least 6 days, within at least 7 days, or within at leastone week. In some embodiments, intravenous and intrathecaladministrations are performed on an alternating schedule, such asalternating administrations weekly, every other week, twice monthly, ormonthly. In some embodiments, an intrathecal administration replaces anintravenous administration in an administration schedule, such as in aschedule of intravenous administration weekly, every other week, twicemonthly, or monthly, every third or fourth or fifth administration inthat schedule can be replaced with an intrathecal administration inplace of an intravenous administration. In some embodiments, anintravenous administration replaces an intrathecal administration in anadministration schedule, such as in a schedule of intrathecaladministration weekly, every other week, twice monthly, or monthly,every third or fourth or fifth administration in that schedule can bereplaced with an intravenous administration in place of an intrathecaladministration. In some embodiments, intravenous and intrathecaladministrations are performed sequentially, such as performingintravenous administrations first (e.g., weekly, every other week, twicemonthly, or monthly dosing for two weeks, a month, two months, threemonths, four months, five months, six months, a year or more) followedby intrathecal administrations (e.g, weekly, every other week, twicemonthly, or monthly dosing for more than two weeks, a month, two months,three months, four months, five months, six months, a year or more). Insome embodiments, intrathecal administrations are performed first (e.g.,weekly, every other week, twice monthly, monthly, once every two months,once every three months dosing for two weeks, a month, two months, threemonths, four months, five months, six months, a year or more) followedby intravenous administrations (e.g, weekly, every other week, twicemonthly, or monthly dosing for more than two weeks, a month, two months,three months, four months, five months, six months, a year or more).

In some embodiments, Hunter Syndrome is associated with peripheralsymptoms and the method includes administering the replacement enzymeintrathecally but does not involve administering the replacement enzymeintravenously to the subject. In certain embodiments, the intrathecaladministration of the I2S enzyme amelioriates or reduces one or more ofthe peripherial symptoms associated with the subject's I2S deficiency

As used herein, the term “therapeutically effective amount” is largelydetermined base on the total amount of the therapeutic agent containedin the pharmaceutical compositions of the present invention. Generally,a therapeutically effective amount is sufficient to achieve a meaningfulbenefit to the subject (e.g., treating, modulating, curing, preventingand/or ameliorating the underlying disease or condition). For example, atherapeutically effective amount may be an amount sufficient to achievea desired therapeutic and/or prophylactic effect, such as an amountsufficient to modulate lysosomal enzyme receptors or their activity tothereby treat such lysosomal storage disease or the symptoms thereof(e.g., a reduction in or elimination of the presence or incidence of“zebra bodies” or cellular vacuolization following the administration ofthe compositions of the present invention to a subject). Generally, theamount of a therapeutic agent (e.g., a recombinant lysosomal enzyme)administered to a subject in need thereof will depend upon thecharacteristics of the subject. Such characteristics include thecondition, disease severity, general health, age, sex and body weight ofthe subject. One of ordinary skill in the art will be readily able todetermine appropriate dosages depending on these and other relatedfactors. In addition, both objective and subjective assays mayoptionally be employed to identify optimal dosage ranges.

A therapeutically effective amount is commonly administered in a dosingregimen that may comprise multiple unit doses. For any particulartherapeutic protein, a therapeutically effective amount (and/or anappropriate unit dose within an effective dosing regimen) may vary, forexample, depending on route of administration, on combination with otherpharmaceutical agents. Also, the specific therapeutically effectiveamount (and/or unit dose) for any particular patient may depend upon avariety of factors including the disorder being treated and the severityof the disorder; the activity of the specific pharmaceutical agentemployed; the specific composition employed; the age, body weight,general health, sex and diet of the patient; the time of administration,route of administration, and/or rate of excretion or metabolism of thespecific fusion protein employed; the duration of the treatment; andlike factors as is well known in the medical arts.

In some embodiments, the therapeutically effective dose ranges fromabout 0.005 mg/kg brain weight to 500 mg/kg brain weight, e.g., fromabout 0.005 mg/kg brain weight to 400 mg/kg brain weight, from about0.005 mg/kg brain weight to 300 mg/kg brain weight, from about 0.005mg/kg brain weight to 200 mg/kg brain weight, from about 0.005 mg/kgbrain weight to 100 mg/kg brain weight, from about 0.005 mg/kg brainweight to 90 mg/kg brain weight, from about 0.005 mg/kg brain weight to80 mg/kg brain weight, from about 0.005 mg/kg brain weight to 70 mg/kgbrain weight, from about 0.005 mg/kg brain weight to 60 mg/kg brainweight, from about 0.005 mg/kg brain weight to 50 mg/kg brain weight,from about 0.005 mg/kg brain weight to 40 mg/kg brain weight, from about0.005 mg/kg brain weight to 30 mg/kg brain weight, from about 0.005mg/kg brain weight to 25 mg/kg brain weight, from about 0.005 mg/kgbrain weight to 20 mg/kg brain weight, from about 0.005 mg/kg brainweight to 15 mg/kg brain weight, from about 0.005 mg/kg brain weight to10 mg/kg brain weight.

In some embodiments, the therapeutically effective dose is greater thanabout 0.1 mg/kg brain weight, greater than about 0.5 mg/kg brain weight,greater than about 1.0 mg/kg brain weight, greater than about 3 mg/kgbrain weight, greater than about 5 mg/kg brain weight, greater thanabout 10 mg/kg brain weight, greater than about 15 mg/kg brain weight,greater than about 20 mg/kg brain weight, greater than about 30 mg/kgbrain weight, greater than about 40 mg/kg brain weight, greater thanabout 50 mg/kg brain weight, greater than about 60 mg/kg brain weight,greater than about 70 mg/kg brain weight, greater than about 80 mg/kgbrain weight, greater than about 90 mg/kg brain weight, greater thanabout 100 mg/kg brain weight, greater than about 150 mg/kg brain weight,greater than about 200 mg/kg brain weight, greater than about 250 mg/kgbrain weight, greater than about 300 mg/kg brain weight, greater thanabout 350 mg/kg brain weight, greater than about 400 mg/kg brain weight,greater than about 450 mg/kg brain weight, greater than about 500 mg/kgbrain weight.

In some embodiments, the therapeutically effective dose may also bedefined by mg/kg body weight. As one skilled in the art wouldappreciate, the brain weights and body weights can be correlated.Dekaban A S. “Changes in brain weights during the span of human life:relation of brain weights to body heights and body weights,” Ann Neurol1978; 4:345-56. Thus, in some embodiments, the dosages can be convertedas shown in Table 5.

TABLE 5 Correlation between Brain Weights, body weights and ages ofmales Age (year) Brain weight (kg) Body weight (kg) 3 (31-43 months)1.27 15.55 4-5 1.30 19.46

In some embodiments, the therapeutically effective dose may also bedefined by mg/15 cc of CSF. As one skilled in the art would appreciate,therapeutically effective doses based on brain weights and body weightscan be converted to mg/15 cc of CSF. For example, the volume of CSF inadult humans is approximately 150 mL (Johanson C E, et al. “Multiplicityof cerebrospinal fluid functions: New challenges in health and disease,”Cerebrospinal Fluid Res. 2008 May 14; 5:10). Therefore, single doseinjections of 0.1 mg to 50 mg protein to adults would be approximately0.01 mg/15 cc of CSF (0.1 mg) to 5.0 mg/15 cc of CSF (50 mg) doses inadults.

It is to be further understood that for any particular subject, specificdosage regimens should be adjusted over time according to the individualneed and the professional judgment of the person administering orsupervising the administration of the enzyme replacement therapy andthat dosage ranges set forth herein are exemplary only and are notintended to limit the scope or practice of the claimed invention.

Kits

The present invention further provides kits or other articles ofmanufacture which contains the formulation of the present invention andprovides instructions for its reconstitution (if lyophilized) and/oruse. Kits or other articles of manufacture may include a container, anIDDD, a catheter and any other articles, devices or equipment useful ininterthecal administration and associated surgery. Suitable containersinclude, for example, bottles, vials, syringes (e.g., pre-filledsyringes), ampules, cartridges, reservoirs, or lyo-jects. The containermay be formed from a variety of materials such as glass or plastic. Insome embodiments, a container is a pre-filled syringe. Suitablepre-filled syringes include, but are not limited to, borosilicate glasssyringes with baked silicone coating, borosilicate glass syringes withsprayed silicone, or plastic resin syringes without silicone.

Typically, the container may holds formulations and a label on, orassociated with, the container that may indicate directions forreconstitution and/or use. For example, the label may indicate that theformulation is reconstituted to protein concentrations as describedabove. The label may further indicate that the formulation is useful orintended for, for example, IT administration. In some embodiments, acontainer may contain a single dose of a stable formulation containing atherapeutic agent (e.g., a replacement enzyme). In various embodiments,a single dose of the stable formulation is present in a volume of lessthan about 15 ml, 10 ml, 5.0 ml, 4.0 ml, 3.5 ml, 3.0 ml, 2.5 ml, 2.0 ml,1.5 ml, 1.0 ml, or 0.5 ml. Alternatively, a container holding theformulation may be a multi-use vial, which allows for repeatadministrations (e.g., from 2-6 administrations) of the formulation.Kits or other articles of manufacture may further include a secondcontainer comprising a suitable diluent (e.g., BWFI, saline, bufferedsaline). Upon mixing of the diluent and the formulation, the finalprotein concentration in the reconstituted formulation will generally beat least 1 mg/ml (e.g., at least 5 mg/ml, at least 10 mg/ml, at least 25mg/ml, at least 50 mg/ml, at least 75 mg/ml, at least 100 mg/ml). Kitsor other articles of manufacture may further include other materialsdesirable from a commercial and user standpoint, including otherbuffers, diluents, filters, needles, IDDDs, catheters, syringes, andpackage inserts with instructions for use.

The invention will be more fully understood by reference to thefollowing examples. They should not, however, be construed as limitingthe scope of the invention. All literature citations are incorporated byreference.

EXAMPLES Example 1: Biodistribution

The major objective of this study was to determine whether recombinanthuman I2S could be delivered to the brain of adult MPS II mice by theintrathecal-lumbar route

TABLE 6 Six groups of 8-12 week old male mice were treated as follows:Dose/Brain Group N Strain Treatment Volume Dose weight Route A 3 IKO I2S10 μL 260 μg 520 mg/kg IT- lumbar B 3 IKO I2S 10 μL 260 μg 520 mg/kg IT-lumbar C 3 IKO Untreated N/A N/A N/A N/A D 1 IKO I2S 10 μL 260 μg 520mg/kg IT- lumbar E 3 IKO Untreated N/A N/A N/A N/A F 3 C57Bl/6 UntreatedN/A N/A N/A N/A Injection schedule: Animals received up to 3 injectionsof idursulfase (10 μL) via the intrathecal-lumbar route: Groups A & D:Administered 3 doses of I2S on days 1, 8, and 15 Group B: Administered 2doses of I2S on days 1 and 8 Groups C & E: Untreated control (IKO) miceGroup F: Untreated wild-type control mice

Materials and Methods

Animals:

Mice were housed in groups of up to 4 per cage in a colony room under a12-hour light-dark cycle. Rodent diet (LabDiet-5001, St Louis, Mo.) andwater (Lexington, Mass. municipal water purified by reverse osmosis) wasavailable ad libitum for the duration of the experiment. Care of animalswas conducted in accordance with the guidelines described in the Guidefor the Care and Use of Laboratory Animals (National Academy Press,Washington D.C., 1996). The current IKO breeding colony was establishedfrom four carrier female mice heterozygous for the IKO mutation thatwere obtained from Dr. Joseph Muenzer (University of North Carolina).Carrier females were bred with male mice of the C57BL/6 backgroundstrain (C57BL/6NTac, Taconic, Hudson, N.Y.), producing heterozygousfemales and hemizygous male knockout mice, as well as wild-type male andfemale littermates. All offspring were genotypes by PCR analysis oftissue DNA. All mice used in this experiment were males identified aseither hemizygous IKO (−/0) or wild-type (WT) littermate (+/0) micebetween 8 and 12 weeks of age.

Idursulfase:

Twenty-two mL I2S [Recombinant human idursufase was dialyzed againstfour changes of 2L phosphate buffered saline (PBS). The I2S was thenconcentrated by Vivaspin column and resuspended in a final volume of 1mL PBS, followed by filter sterilization using a 0.2 μm filter. Thefinal concentration was 51 mg/mL.

Intrathecal-Lumbar Injections:

Adult mice were anesthetized using 1.25% 2,2,2 tribromoethanol (Avertin)at 200-300 μL/10 grams body weight (250-350 mg/kg) by intraperitonealinjection. Dorsal hair was removed between the base of the tail and theshoulder blades and the shaved area was swabbed with povidine/betadinescrub followed by isopropyl alcohol. A small midline skin incision (1-2cm) was made over the lumbosacral spine and the intersection of thedorsal midline and the cranial aspect of the wings of the ilea (singularileum) identified. The muscle in the iliac fossa (gluteus medius) is aheart shaped muscle and the two sides of the top of the “heart”approximate the location of the wings of the ilea. A 32 gauge needleattached to a gas tight 10-20 μL glass Hamilton syringe was inserteduntil resistance was felt from the underlying bone. Injection of 10 μLof test article at an approximate rate of 2 μL/20 seconds (10 μL/2minutes) was performed. The skin incision was closed using wound clipsas appropriate and the animal was allowed to recover in a recoverychamber before being returned to the appropriate cage.

Histology Procedures:

Animals were sacrificed at one hour after the final injection.

Brain and liver tissues were collected and fixed in 10% neutral bufferedformalin, then processed and embedded in paraffin. Five μm sections wereprepared for hematoxylin/eosin (H&E) and immunohistochemistry (IHC)staining.

Hematoxylin and Eosin Staining:

Brain and liver sections were stained with H&E. The staining resultsshowed nuclei as purple and cytoplasm as pink to red. H&E stained slideswere used for histopathological morphology evaluation.

Immunohistochemistry:

For I2S biodistribution evaluation, deparaffinized and rehydrated brainand liver sections were incubated overnight with mouse monoclonalantibody 2C4-2B2 (Maine Biotechnology Services, Portland, Me.) againstrecombinant human I2S to detect injected I2S (or an irrelevant mouse IgGas a negative control antibody; Vector Laboratories, Burlingame,Calif.). Following an overnight incubation at 2-8° C., a secondary goatanti-mouse IgG conjugated with horseradish peroxidase was added. Afteradditional 30 minutes of incubation at 37° C., Tyramide-Alexa Fluor 488labeling solution (Invitrogen Corp., Carlsbad, Calif.) was added for anadditional 10 minutes. Sections were coverslipped using an antifadingmounting medium (VectaShield; Vector Laboratories) containing 1.5 μg/ml4′-6-diamidino-2-phenylindole (DAPI) as a nuclear counterstain andobserved with a multiple channel Nikon fluorescent microscope. Thestaining results showed I2S positive cells as green, with nuclei asblue, and background areas as black.

For efficacy analysis, brain and liver sections were stained with a ratanti-LAMP-1 (lysosomal associated membrane protein as a lysosomalmarker) IgG (Santa Cruz Biotechnology, Santa Cruz, Calif.) as theprimary antibody. A rat IgG as an irrelevant antibody was used asnegative control. The ABC (avidin biotin complex kits from Vector Labs,Burlingame, Calif.) method was used to amplify the targeted marker.

Briefly, deparaffinized sections were rehydrated and incubated with theprimary antibody. Following overnight incubation at 2-8° C., a secondarybiotinylated rabbit anti-rat IgG (Vector Labs, Burlingame, Calif.) wasadded and incubated 30 minutes at 37° C., then samples were washed andtreated with avidin-biotin-peroxidase complex (Vector Laboratories) for30 minutes. For color development, 3,3-diaminobenzidinetetrahydrochloride (DAB) was used as the chromagen. Sections were thencounterstained with hematoxylin and coverslipped. The staining resultsshowed LAMP-1 positive cells as brown and nuclei as blue.

The representative photos were taken and the area of LAMP-1 positivecells was analyzed with Image-Pro Plus software (Media Cybernetics,Inc., Bethesda, Md.) and comparative statistics were performed usingstudent's t-test.

Electron Microscope Method:

Brain tissues from 3 doses of I2S treated animals were fixed in 2.5%PFA/2.5% glutaraldehyde in 0.1M sodium cacodylate buffer pH 7.4 at 4degrees for over night. Then the samples were washed in cacodylatebuffer (0.1M, pH7.4) and post-fixed in osmium tetroxide, dehydrated inalcohols and propylene oxide and embedded in Epon resin. Ultrathinsections were cut at 100 nm, stained with lead citrate and examined in aTecnai™ G² Spirit BioTWIN transmission electron microscope.

Results

In the brain as determined by immunohistochemistry (IHC), no I2S wasfound in vehicle control animals. In contrast, meningeal cells, neuronsof the cerebrum and cerebellum were positively stained for I2S in I2Sinjected animals. The staining signal was stronger in animalsadministered 3 doses (FIG. 1).

In brain tissues of vehicle-treated IKO mice, cellular vacuolation, ahistopathological hallmark of lysosomal storage diseases, was foundthroughout brains compared to wild type animals. In I2S treated IKOmice, there was widespread reduction of cellular vacuolation from thesurface cerebral cortex, caudate nucleus, thalamus, cerebellum, to thewhite matter compared to untreated ones (FIG. 2). Abnormally highlysosomal activity was found by lysosomal-associated membrane protein-1(LAMP-1) staining, an indicator of lysosomal activity and disease state,in microglial, meningeal and perivascular cells of vehicle-treated IKOmice when compared to wild type animals. The I2S intralthecal-treatedmice had marked reductions in LAMP-1 immunostaining. This reduction wascharacterized by the decrease in the number of LAMP-1 positive cells andlighter staining. The reduction was found throughout whole brain fromthe surface cerebral cortex, caudate nucleus, thalamus, cerebellum towhite matter (FIG. 3) in both 2 and 3 dose of I2S treated animals.Morphometrical analysis of LAMP-1 immunostaining of various brainregions confirmed that there were significant reductions in the LAMP-1positive staining in all areas of the brain evaluated (FIG. 4).

Electron microscopy examination of brain cells in vehicle-treated IKOmice revealed the enlarged vacuoles containing amorphous granularstorage material and inclusions with lamellated and zebra body-likestructures. These typical pathological features of lysosomal storage atthe ultrastructural level were reduced in I2S intrathecal-lumbarinjected mice (FIG. 5).

In the liver, there was no positive staining of I2S in the vehicletreated animals. In the I2S intrathecal injected mice, a large amount ofinjected I2S was clearly found in sinusoidal cells (FIG. 6), whichindicated the injected I2S within the intrathecal space circulated withCSF and was then absorbed through the arachnoid granulations into thecirculatory system.

In liver tissues of vehicle-treated IKO mice, severe cellularvacuolation and abnormally high lysosomal activity demonstrated by H&Estaining and strong LAMP-1 immunostaining were found compared to WTmice. Marked reduction of cellular vacuolation and LAMP-1 immunostainingin livers was found after intrathecal treatment with I2S. H&E stainingrevealed intracytoplasmic vacuolization was almost completely disappearwith a nearly normal liver cell structure (Figure. 7).

In IKO mice, recombinant human I2S was delivered to the brain by theintrathecal-lumbar route and injected I2S cause widespreadhistopathological improvement in a variety of regions in the brain.

-   -   Injected I2S was detected in meningeal cells and neurons in the        brain.    -   Reduced cellular vacuolation throughout the brain at both light        and electron microscopy levels.    -   Reduced LAMP-1 lysosomal marker throughout the brain.    -   Intrathecal injected I2S entered the peripheral circulation and        improved liver morphology and histological marker.

Example 2: Toxicology

This example illustrates the clinical signs associated with idursulfasevia monthly bolus intrathecal lumbar doses in cynomolgus monkeys. Toachieve this, 14 male, cynomolgus monkeys were randomly assigned to fivetreatment groups as shown in the following table.

TABLE 7 EXPERIMENTAL DESIGN Group Number of Animals Nominal Dose (mg)Dose Volume (ml) 1 3 0 1 2 3 3 1 3 3 30 1 4 3 150 1 5 2 100 1

Animals in all groups were dosed three times at monthly intervals IT atthe level of the lumbar spine. The 1 ml dose volume was flushed from thecatheter system with 0.3 ml of PBS. One to two days prior to eachdosing, approximately 2 ml of CSF was collected from an IT spinal tap atthe level of the cisterna magna. Blood samples (2 ml) were alsocollected at this time. Blood (2 ml) and CSF (0.1 ml) were collectedfrom Group 5 animals predose, 0.5, 1, 2, 4, 8, 24, and 48 hours postdose after the first dose. Clinical signs were recorded at least twicedaily. A necropsy was performed approximately 24 hours after the thirddose and selected tissues were harvested and saved.

On Day 1, all three Group 4 (150 mg) animals exhibited minimal tendingto hind quarters within 3-12 minutes post dose, lasting 5-15 minutes;this sign was deemed related to the test article. There were no changesin body weight, food consumption and neurological/physical examinationparameters that were considered related to the test article.

The analysis of the serum and CSF samples and the dosing solutionanalyses are presented. Variations in endogenous idursulfase activitywere observed in different tissues from the cynomolgus monkey; brain andspinal cord had greater endogenous activity than other peripheral organsexamined, including liver, heart, and kidney. Idursulfase administrationwas associated with dose-dependent increases in idursulfase activity invarious brain regions, as well as in the brainstem and spinal cord. ITdelivery did not result in an observable difference in distributionbetween the right and left cerebral hemispheres. There was a cleardose-dependent increase in idursulfase activity in the following organs:brain, liver, heart, and kidney. Immunostaining for idursulfase in thebrain demonstrated a dose-dependent increase in staining intensity. Inthe 3 mg group, meningial cell and limited glial cell staining beneaththe meninges was observed; neuronal staining was not evident in animalsfrom the 3 mg treatment group. Idursulfase staining was positive anddose dependent in the spinal cord, with the highest staining intensityin the lumbar region, where IT administration of idursulfase occurred.Idursulfase staining intensity in liver, kidney, and heart wasdose-dependent and consistent with increased idursulfase activity inthese organs.

In conclusion, IT administration of idursulfase at doses up to 150 mgdelivered at monthly intervals had no adverse effects. Thus, the noobserved adverse effect level (NOAEL) was interpreted to be 150 mg, thehighest dose tested in this study. Idursulfase administration wasassociated with dose-dependent increases in idursulfase activity in theCNS and resulted in systemic I2S levels and activity in the liver,kidney, and heart.

The test article, idursulfase, was supplied as dosing solutions in 154mM NaCl, 0.005% Polysorbate 20, pH 5.3-6.1. The nominal concentrationsof the supplied dosing solutions were 0, 3, 30 or 150 mg/ml. The testarticle was stored in a freezer at −82° to −79° C. Phosphate bufferedsaline (PBS), pH 7.2, was used as a flushing agent after the doses wereadministered and after serial CSF collections. The PBS was obtained fromGibco, Invitrogen Corporation.

Test Article Dosing Preparation

On the first day of dosing for each time interval, one vial of eachconcentration was removed from the −80° C. chest freezer and allowed tothaw on the countertop to room temperature. Once thawed, the vials forGroups 1, 2, and 3 were labeled, weighed and 1 ml was withdrawn througha 0.22 μm filter for each animal scheduled for dosing. After all of thedoses were administered, the vials were reweighed and placed in therefrigerator.

The following day (day of dosing for Animal 003, Group 4, and Group 5)dosing solutions for Groups 1 and 4 were removed from the refrigeratorand placed on the countertop to reach room temperature. Once roomtemperature was obtained, the vials for Groups 1 and 4 were weighed,Group 4 vial was labeled, and 1 ml was withdrawn through the filter foreach animal scheduled for dosing in Groups 1 and 4. The dosing solutionfor Group 5 was then prepared by injecting the appropriate amount ofGroup 4 dosing solution and Group 1 (vehicle) into a sterilepolypropylene vial. The amount added from Groups 1 and 4 were recorded.The solution was mixed by gently inverting the vial and 2-1 ml doseswere withdrawn through the filter for the animals in Group 5. The vialsfor Groups 1 and 4 were reweighed upon completion of dosing and all thevials (Groups 1-5) were placed in a freezer.

Fourteen animals were randomly assigned to treatment groups as describedin the following Table.

The IT route of administration was selected because this is an intendedroute for human administration. he doses of idursulfase that wereselected for this study (3, 30, 100, and 150 mg/ml) were chosen toassess the biodistribution of varying doses levels of enzyme within thenon-human primate central nervous system (CNS) after three consecutivemonthly bolus IT lumbar injections.

Clinical Observations

The overall incidence of clinical signs was minimal. None of the animalsin Group 1 (control), Group 2 (3 mg), Group 3 (30 mg), or Group 5 (100mg) had clinical signs that were considered related to the test articleat any time during the study.

On Day 1, all three Group 4 (150 mg) animals (012-014) exhibited minimaltending to hind quarters within 3-12 minutes post dose, lasting 5-15minutes. This sign was considered related to the test article and wasnot observed in any of the lower dose groups. There were no otherclinical signs immediately after the first dose or on the daysimmediately following test article administration. The only other signobserved for the Group 4 animals was a single episode of emesis forAnimal 013 on Day 35.

Administration of the test article as a single, monthly intrathecalbolus was not associated with any adverse gross or microscopic changewhen taking into consideration the changes inherent with an implanteddrug delivery device. All groups, including the control group, hadmicroscopic changes in the meninges indicating inflammatory reactions tothe drug delivery system. In the animals that received doses of the testarticle of 30 mg and greater, there was a tendency for the inflammatoryreaction in the meninges to have a more pronounced eosinophiliccomponent.

Because the differences between the control and test article treatedanimals were so slight, the no observed adverse effect level (NOAEL) wasinterpreted to be 150 mg, the highest dose tested in this study.

The overall inflammatory reaction in the meninges in all groups(including controls) was slightly more pronounced than generallyencountered in an intrathecal study of this duration in monkeys.However, this was considered to possibly be related to somecharacteristic of the vehicle or to the act of dosing 24 hours prior tonecropsy.

Brain idursulfase staining was positive in all treated animals exceptone animal in the 3 mg group, with the highest staining intensity foundin the 150 mg group (FIGS. 16, 17, 18 and 19). In the 3 mg group, onlymeningial cells and a few glial cells beneath the meninges werepositive; no injected idursulfase was detected in neurons. In the higherdose groups (30, 100 and 150 mg), large populations of cerebral neuronswere strongly positive for idursulfase staining, along with meningialcells, glial cells and perivascular cells. Idursulfase immunostainingrevealed a wide distribution of injected idursulfase in cerebral neuronsfrom the neurons within layer I at the surface near the meninges, to theones within the deeper layer VI adjacent to the white matter (FIGS. 20,21 and 22). Marked staining of neurons was also observed for the 150 mgdose group (FIG. 23). In all animals (dose group from 30-150 mg), nomarked difference in the neuronal idursulfase staining was found betweenfrontal, middle, and rear sections of the brain.

Idursulfase staining was positive in the spinal cords of all animals,with the highest staining intensity in the lumbar region (FIGS. 24 and25). Idursulfase immunostaining was also dose dependent. Neurons,meningial cells, glial cells, perivascular cells andepi/peri/endoneurium (connective cells) surrounding nerve fibers werestrongly positive for idursulfase staining in the 150 mg group (FIGS. 26and 27).

In the liver, positive staining for idursulfase was found in sinusoidalcells (Kupffer cells and endothelial cells) of all animals. Idursulfase,however, was not detected in hepatocytes for the 3 mg treatment group(FIG. 28), while positive idursulfase staining in the hepatocytes wasfound in the higher dose groups, with the greatest staining intensity inthe 150 mg treatment group (FIGS. 29, 30 and 31).

There was no positive staining for idursulfase in animals from the 3 mgtreatment group (FIG. 22). In contrast, interstitial cells werepositively stained for idursulfase in the 30, 100 and 150 mg groups,with marked staining being observed in the 150 mg group—in terms ofpositive cell number and staining intensity (FIGS. 33, 34 and 35).

Kidney

Little or no injected idursulfase was detected in animals from the 3 mgdose group (FIG. 36). Positive idursulfase staining, however, was foundin the glomerular cells and interstitial cells in the 30 and 100 mggroups (FIGS. 37 and 38). In the 150 mg group, idursulfaseimmunostaining additionally revealed idursulfase staining of proximaltubular cells, along with marked staining of glomerular and interstitialcells (FIG. 39).

DISCUSSION

There were no test article-related clinical signs or effects on bodyweight, food consumption, physical examination findings and neurologicalexamination findings. On Day 1, the Group 4 (150 mg) animals exhibitedminimal tending to hind quarters within 3-12 minutes post dosing,lasting 5 to 15 minutes; this sign was judged to be related to the testarticle.

Idursulfase administration was associated with dose-dependent increasesin idursulfase activity in various brain regions, as well as the brainstem and spinal cord. The highest level of staining intensity in thespinal cord was in the lumbar region, where IT administration ofidursulfase occurred. IT administration of idursulfase also resulted insystemic exposure with dose-dependent staining intensity in the liver,kidney, and heart. Animals that received doses of the test article at 30mg and greater had a tendency for the inflammatory reaction in themeninges to have a more pronounced eosinophilic component, but thisdifference was not considered biologically significant.

IT administration of idursulfase at doses up to 150 mg delivered atmonthly intervals had no adverse effects. Thus, the no observed adverseeffect level (NOAEL) was interpreted to be 150 mg, the highest dosetested in this Example. Idursulfase administration was associated withdose-dependent increases in idursulfase activity in the CNS and resultedin systemic levels in the liver, kidney, and heart.

Example 3: PK (Serum and CSF) of IT Delivered I2S

This example provides serum and cerebrospinal fluid (CSF) analysisassociated with a 6-Month Toxicity Study of ldursulfase Administered ViaMonthly Bolus lntrathecal Lumbar injections and Weekly Bolus IntravenousInjections in Cynomolgus Monkeys” for test article (TA) concentration.

Experimental Design

The objective of this study was to evaluate repeat dose intrathecal (IT)administration of idursulfase (12 s) from a toxicology and safetypharmacology perspective over a six month period. The study design isshown in Table 8.

TABLE 8 STUDY DESIGN Group Number of IV Dose No. of IV IT Dose No. of ITNo. Animals (mg/kg) Doses (mg) Doses 1 6 DC (saline) 23 DC (PBS) 6 2 120 (IV vehicle) 23 0 (IT vehicle) 6 3 12 0.5 23 3 6 4 6 0.5 23 30 6 5 120.5 23 100 6 DC = Device Control: Animals In group 1 not dosed withvehicle or test article. Test Article Identification: Idursulfase IVDosing-(2.0 mglmL) IT Dosing-idursulfase (0 mgImL) idursulfase (3 mglmL)idursulfase (30 mg/ml) idursulfase (100 mg/ml)

Assay Methods:

Analyses were conducted using an EL1SA (Enzyme Linked lmmunosorbentAssay) for determining idursulfase concentration. The limit of detection(LOD)=1.25 ng/mL prior to multiplying by dilution factor. Samples werescreened at a 1:50 dilution, therefore the assay sensitivity is 62.5ng/mL. Samples falling beyond the high end of the calibration curve werefurther diluted and retested at an appropriate dilution that resulted ina value within the range of the curve. Selected samples wereadditionally analyzed using an enzyme activity assay. The LOD for thisassay is 0.18 mU/mL at a minimal sample dilution of 1:150.

Animals in groups 1 and 2 that were dosed with saline or vehicle,respectively, all had serum idursulfase levels ranging between 138 ng/mLand <62.5 ng/mL (or <LOD) throughout the period of IV and IT dosing. Of200 CSF samples tested from Group 1 and 2 animals, 62 demonstratedlevels of I2S above the assay LOD. Of these, 7 values were high (>1,000ng/mL). One other CSF sample collected pre IT dose 3 tested above 1,000ng/mL of I2S.

The samples were then tested for idursulfase activity. In each case theactivity results indicated the presence of 12S and when the approximateconcentration of 12S was calculated based on the activity levels, theresults were within 20% of those obtained by the antigen ELISA. (SeeTable 9) Additional randomly chosen CSF samples with antigen ELISAresults <LOD were also tested using the enzyme activity assay to ruleout any non-specific activity.

TABLE 9 INVESTIGATION RESULTS FROM CSF SAMPLES Calculated ELISA Activityng/mL Calculated Animal Dose Dose Time Result Result Based on as % ofNumber Group Dose Number Mode Point (mg/mL) (mU/mL) Activity Measured003 1 Saline 5 IT Predose 1392 4.7 1173 119% 003 1 Saline 6 IT Predose7322 29.9 7469  96% 004 1 Saline 2 IT 2 hr 17045 62.1 15527 110% post006 1 Saline 6 IT 4 hr 16435 70.7 17682  93% post 006 1 Saline 1 ITPredose 1320 5.3 1319 100% 0016 2 Vehicle 1 IT 2 hr 3070 11 2743 112%post 017A 2 Vehicle mo. 3 IV 4 hr 2236 8.8 2194 102% post 046 5 100 3 ITPredose 2086 7 1750 119% mg/kg

In this study, serum and CSF samples were analyzed for idursulfaseconcentration. Serum samples were collected according to the followingschedule:

IV Doses: predose and 2 hours post doses 1 through 10, predose and 4hours post doses 11 through 23, and at necropsy.

IT Doses: predose and 2 hours post doses 1 and 2, predose and 4 hourspost doses 3 through 6, and at necropsy.

CSF samples were collected according to the following schedule:

IV Doses: predose and 2 hours post dose 1, and 4 hours post doses 3 and6.

IT Doses: predose and 2 hours post doses 1 and 2, predose and 4 hourspost doses 3 through 6, and at necropsy.

Generally, serum idursulfase cleared faster than CSF idursulfase.

Serum idursulfase levels in groups 1 and 2 animals that were dosed withsaline or vehicle, respectively, were less than or equal to 138 ng/mL atall time points tested. Some animals had levels below the assay limit ofdetection (LOD).

Fewer CSF samples from groups 1 and 2 were above the assay LOD, with 7notable exceptions that resulted in high (>1,000 ng/mL) levels. One CSFsample collected from an animal pre IT dose 3, also tested above 1,000ng/mL idursulfase.

The samples giving these out-of-trend results were retested andconfirmed. In addition, these samples were tested for idursulfase enzymeactivity. These activity results also confirmed high idursulfase levelswithin 20% of those obtained by the idursulfase mass assay (Table 9).

The specificity of the activity assay was validated within this samplecohort by randomly testing CSF samples with idursulfase mass units belowLOD and confirmed that idursulfase levels in these samples were indeedLOD (data not shown).

Example 4: Formulation

This Example summarizes the pharmaceutical development studies performedto establish the formulations of Idursulfase-IT Drug Substance and DrugProduct for Phase I/II clinical trials.

Due to the limitation of the excipients suitable for the CNS delivery,the effort for the formulation development for intrathecal delivery ofidursulfase was focused on reducing the phosphate and polysorbate 20level while still maintaining the stability equivalent to the I2Sformulation for systemic delivery.

Three key screening stress studies were conducted to examine the effectof phosphate and polysorbate level. These included freeze thaw, shakingstress, and thermal stresses. The results demonstrated the salineformulation is more stable against the freeze thaw stress at low proteinconcentration (2 mg/mL). At high protein concentration (100 mg/mL), thefreeze thaw stress did not cause instability issue for both saline andphosphate containing formulations. The shaking stress study confirmedthat 0.005% polysorbate 20 protected the protein against shaking relatedstress. The thermal stability studies demonstrated that the salineformulation was more stable compared to the formulations containingphosphate. In addition, the pH of the saline formulation can bemaintained at 6.0 for 24 months at 2-8° C. The amount of residualphosphate associated with the protein, as well as the increased proteinconcentration was found to contribute to the pH stability in the finalformulation.

Methods

Effect of Freeze/Thaw Stress on Stability of Idursulfase in Saline andPhosphate Formulations

To examine the effect of freeze/thaw on idursulfase stability indifferent formulations, the viral SEC pool was exchanged/concentratedusing a Centricon Plus four times into either 150 mM NaCl or 137 mM NaClwith 20 mM sodium phosphate (both at pH 6.0). The protein concentrationswere targeted to 2 mg/ml and 100 mg/mL. All solutions were filteredthrough a 0.22 micron PVDF filter. The solutions were aliquotted at 1 mLeach into 2 mL borosilicate glass vials. The vials were placed on themiddle shelf of a lyophilizer chamber and surrounded by placebo vials.The samples were frozen at a programmed freeze/thawing cycle (held for 1hour at 20° C. and frozen to −50° C. at 1° C./min.) Then, thawed in twosteps at a rate of 0.03° C./min from −50° C. to −25° C., held for 24hours at −25° C., and allowed to thaw to 2-8° C.). After two or threefreeze/thawing cycles, the samples were analyzed by appearance andSEC-HPLC assays.

Effect of Shaking/Shear Stress on Idursulfase in Phosphate and SalineSolutions

Shaking studies were performed on the idursulfase at different proteinconcentrations. The protein concentrations were tested at 2 mg/mL, 8mg/mL, and 90-100 mg/mL in the present of 137 mM NaCl in 20 mM phosphate(pH 6.0) and 154 mM NaCl (pH 6.0) alone. To see if polysorbate wasneeded, various amounts of PS-20 were spiked into the test condition.The solutions were aliquoted at 1.2 mL each in 2 mL glass vials and thenshaken on an orbital shaker at 250 rpm under ambient conditions for 24hours. At baseline and 24 hours, the appearance was examined, and 0.1 mLaliquots were sampled in frozen at below ≤−65° C. in 0.5 mLpolypropylene tubes until analysis by SEC-HPLC.

To first confirm the effect of polysorbate 20 level, a simulatedshipping study was conducted using a 3 hour truck shipment of materialfollowed by a 1 hour air test at Assurance Level 1 using random testoptions (conducted by Lansmont (Lansing, Mich.)). The samples wereanalyzed for appearance of particles and soluble aggregates by SEC-HPLC.

To examine the effect of stirring stress on the stability, a salineformulation (50 mg/mL, 154 mM NaCl, and 0.005% PS-20) was filled at 1.3mL in a 3 mL type I glass vial and stoppered with a 13 mm stopper, whichcontained a Teflon coated magnetic stir bar (8 mm in length and 2 mm indiameter). The vials were placed on a stir plate set at speed setting 6(the choice of setting 6 was maximal speed without causing excessivefoaming). Appearance was determined at 0, 2, 24, 48, and 72 hours. Thebaseline and the 72 hour stirred samples were tested SEC-HPLC methods.

Thermal Stability Studies for Lead Formulations

Six lead formulations were compared for thermal stability. Theseformulations were chosen based on two parameters. The first parameterwas that the protein concentration needed to be within therapeuticranges for CNS delivery. The second parameter was to control the effectof phosphate concentration on the stability. The viral filtered SEC poolwas buffered exchanged and concentrated using the Centricon Plus-80.Target concentrations of 50 and 100 mg/mL protein concentrations wereachieved. The six formulations were spiked with a 1% polysorbate 20solution for a final concentration of 0.01% PS-20. The material wasfiltered through a 0.22 micron PVDF filter and 0.5 mL added into 2 mLglass borosilicate vials. These vials were placed on stressed stability(40° C.), accelerated stability (25° C.), and real time storage (2-8°C.) in an inverted position. The stability samples at each time pointwas tested by SEC-HPLC, OD320, SAX-HPLC, SDS-PAGE (Commassie), pH, andactivity.

Understanding the pH Control in Saline Formulation

To understand how the pH in the saline formulation was maintained, thefollowing studies were conducted.

Testing the Residue of Phosphate in Saline Formulations

The viral filtered SEC pool (2 mg/mL idursulfase, 137 mM NaCl, 20 mMsodium phosphate, pH 6.0) was concentrated and diafiltered into 150 mMNaCl by using the Millipore TFF system and a Millipore Pellicon Biomax30, 50 cm² filter. The samples were to determine the amount of phosphateassociated with protein after 7×, 10× and 15× cycles of diafiltrationinto 0.9% saline (prepared at TK3). In addition, the permeate after 10×diafiltration (non-protein containing flow through from filtration) andthe saline used in the filtration step were also tested.

Determining the Effect of Protein Concentration on pH

To better understand the control of the pH without the presence of abuffer (phosphate), protein effect studies were conducted. To determinethe contribution of the protein on pH, material was diluted in 154 mMNaCl (saline) to 30 mg/mL, 10 mg/mL, 2 mg/mL, 1 mg/mL, 0.1 mg/mL, 0.01mg/mL and saline alone. The material was aliquotted into 2 mLpolypropylene tubes at a fill volume of 1 mL per tube. The samples werefrozen at ≤−65° C. for 1 hour, thawed at ambient for 30 minutes, and thecycle repeated three times. The initial pH was measured and comparedafter 3× freeze/thaw cycles. The pH was also measured after 24 hoursambient exposure (by opening the caps of the tubes) of the samples todetermine the effect protein concentration may have on pH shift.

Due to the limitation of the excipients suitable for the CNS delivery,the effort for the formulation development for intrathecal delivery ofidursulfase was focused on reducing the phosphate and polysorbate 20level while still maintaining the stability equivalent to I2S formulatedfor systemic administration. Three key screening stress studies wereconducted, including freeze thaw, shaking stress, and thermal stresses.

Effect of Freeze/Thaw on Idursulfase in Saline and PhosphateFormulations

As shown in Table 10, at low protein concentration of 2 mg/mL, the 20 mMphosphate containing formulation generated more aggregates after thefreeze thaw stress. The saline formulation remained at the same level ofaggregates as the baseline. At high protein concentration (100 mg/mL),the freeze thaw stress appeared to have no effect on the stability ineither of formulations (Table 11). The data indicated that the salinealone formulation has better stability against freeze thaw stress.

TABLE 10 SOLUBLE AGGREGATION AT LOW PROTEIN CONCENTRATION 2 mg/mL in 20mM Phosphate, 2 mg/mL in Saline, pH 6.0* pH 6.0 % HMW species % HMWspecies Baseline 0.02% 0.05% Post freeze thawing  1.7% 0.04%

TABLE 11 SEC PROFILE TO DETERMINE SOLUBLE AGGREGATION AT HIGH PROTEINCONCENTRATION 100 mg/mL in 20 mM 100 mg/mL in Saline, Phosphate, pH 6.0*pH 6.0 Baseline 0.05% 0.06% Post freeze thawing 0.04% 0.07% *The amountof NaCl was adjusted to 137 mM where the formulation contained 20 mMphosphate to maintain comparable tonicity.

Effect of Shaking Stress on Idursulfase in Solution

The shaking studies were conducted at three protein concentration levelsof 2, 8, and 100 mg/mL. The data demonstrated that without polysorbate20, precipitates occurred at all the protein concentration and also highlevel of soluble aggregates was observed at 2 mg/mL (Table 12 toTable14). However, in the presence of very low level of P20 such as 0.005%,the precipitates and soluble aggregates were mostly prevented. The dataindicated that a low level of polysorbate is required to protect theprotein against shaking stress.

Tables 12-14: Shaking Study in a Lab Model (Rotation at 250 Rpm for 24Hours at Ambient)

TABLE 12 ~2 mg/ml in 137 mM NaCl and 20 mM Phosphate at pH 6 P20Concentration Appearance SEC (% monomer)    0% Protein-like particlesobserved 95.2% 0.0005% Protein-like particles observed 99.4%  0.001%Protein-like particles observed 99.4% 0.0025% Dust-like particlesobserved 99.7%  0.005% Dust-like particles observed 99.7%  0.01%Dust-like particles observed 99.8%

TABLE 13 ~8 mg/ml in 137 mM NaCl and 20 mM Phosphate at pH 6 SEC SampleAppearance (% monomer) Without PS-20 Protein-like particles observed99.3% (shaken) 0.005% No particles observed 99.7%

TABLE 14 90-100 mg/ml in Saline formulation SEC P-20 ConcentrationAppearance (% monomer) Without PS-20 Large protein-like particles 100.%observed 0.005% Some particles observed 99.8  0.01% No particles 99.9*The control sample (without shaking) had 99.8% monomer.

To further confirm whether the 0.005% is sufficient for the stabilityagainst shaking, a simulated shipping study, which was close to the realshipping condition, was conducted on the saline formulation at 100 mg/mLprotein with different level of polysorbate 20. The results confirmedthat 0.005% was sufficient (Table 15).

TABLE 15 EFFECT OF POLYSORBATE 20 ON APPEARANCE AND SOLUBLE AGGREGATESOF 100 MG/ML IN SALINE AFTER A SIMULATED SHIPPING STUDY Polysorbate 20Appearance SEC (% monomer) 0 (control) No particles 99.8% No shippingstress 0 <10 small particles observed 99.9% 0.005% No particles 99.8% 0.01% No particles 99.8%

The effect of stirring using a magnetic stir bar on the stability of thesaline formulation containing 50 mg/mL idursulfase with 0.005%polysorbate 20 is summarized in TableTable 16. As shown, the protein isnot susceptible to the stress caused by stirring using a magnetic stirbar for 72 hrs. The results confirmed that 0.005% was sufficient againststirring stress as well.

TABLE 16 EFFECT OF POLYSORBATE 20 ON 53 MG/ML IDURSULFASE STABILITY UPONAGGRESSIVE STIRRING SEC-HPLC, Appearance monomer % Baseline 2 hr 24 hr48 hr 72 hr Baseline 72 hr no ppt no ppt no ppt no ppt no ppt 99.96%99.94%

Thermal Stability for the Lead Candidates

Six key formulations were examined over 24 months for stability testing.The results of these tests are discussed in this section.

Appearance

The appearance of all of the formulations remained slightly opalescentand essentially particle free under all of the temperatures andtimepoints tested for the six formulations.

OD320

To examine the potential increases in turbidity, the OD320 values weredetermined and summarized in Table 17 Table. As shown, in the frozenstorage, the OD320 values for all the formulations remained the same asthe baseline after 24 months storage. At 2-8C condition, the salineformulations remained the same as the baseline after 24 months but thephosphate containing formulations had an increased level in OD320values. At the accelerated condition of 25C, the saline formulationsalso had a slight increase in OD320 after 3-6 months but the phosphatecontaining formulations showed a more significant increase. Theseresults suggest that the saline formulation is more stable againstthermal stress.

TABLE 17 COMPARING OD320 FOR SALINE AND PHOSPHATE FORMULATIONS * 50 100100 mg/ml, mg/ml, mg/ml, 50 100 150 mM 150 mM 137 100 mg/ml, mg/ml,mg/ml, NaCl, NaCl, NaCl, 137 NaCl, 154 mM 154 mM 5 mM 5 mM 20 mM 20NaCl, NaCl, NaPO₄, NaPO₄, NaPO₄, mMNaPO₄, pH 6.0 pH 6.0 pH 6.5 pH 6.5 pH6.0 pH 6.5 ≤−65° C. Baseline 0.026 0.043 0.025 0.042 0.042 0.044 16months 0.027 0.043 0.029 0.045 0.045 0.046 24 months 0.023 0.046 0.0240.068 0.045 0.046 25° C.  3 months 0.043 0.076 0.065 0.116 0.124 0.137 6 months 0.040 0.077 0.064 0.110 0.122 0.138 2-8° C.  3 months 0.0280.047 0.034 0.053 0.071 0.072  6 months 0.028 0.049 0.040 0.067 0.0860.090 16 months 0.027 0.051 0.049 0.089 0.102 0.111 24 months 0.033 n/a0.056 0.099 0.110 0.113 * All contain 0.01% Polysorbate 20

SEC-HPLC

The data summary of all the formulations tested by SEC-HPLC is listed inTable. At the frozen storage conditions, there was no change after 24months compared to the baseline.

At the stressed condition of 40° C., after two weeks all theformulations had increased levels of soluble aggregates. In addition,the phosphate containing formulations also showed a “12 min” peak.However, after 1 month, the “12 min peak” peaks observed in thephosphate containng formulation seemed to disappear. In addition, thesoluble aggregate level did not further increase for all theformulations compared to the 2 week time point (FIG. 8 and Table 18).

At the accelerated condition of 25° C., compared to the baseline, forall the formulations, the increased level of soluble aggregates wasminimal after 6 months. However, all the phosphate containingformulations showed the “12 min” peak (FIG. 9 and Table 18 Table).

At the long term storage condition of 2-8° C., after 24 months theincrease of the soluble aggregates for all the formulation was alsominimal after 24 months storage. Consistent with all conditions, thephosphate containing formulations also had the “12 min peak”, whichincreased slightly over time (FIG. 10 and Table 18 Table)

These results indicate that the saline formulations had the leastchanges compared to the phosphate containing formulations at all thestorage condition.

TABLE 18 COMPARING AGGREGATION BY SEC-HPLC IN SALINE & PHOSPHATEFORMULATIONS* 50 100 100 mg/ml, mg/ml, mg/ml, 50 100 150 mM 150 mM 137100 mg/ml, mg/ml, mg/ml, NaCl, NaCl, NaCl, 137 NaCl, 154 mM 154 mM 5 mM5 mM 20 mM 20 NaCl, NaCl, NaPO₄, NaPO₄, NaPO₄, mMNaPO₄, pH 6.0 pH 6.0 pH6.5 pH 6.5 pH 6.0 pH 6.5 ≤−65° C. Baseline 99.9 99.9 99.9 99.8 99.9 99.9 6 months 99.9 99.9 99.8 99.8 99.8 99.8 (0.03)^(a ) 16 months 99.9 99.899.9 99.8 99.8 99.9 24 months 99.8 99.8 99.8 99.9 99.8 99.8 (0.21)^(a )40° C.  2 weeks 97.9 97.8 97.9 97.8 97.4 97.5 (0.23)^(a ) (0.20)^(a)(0.34) ^(a) (0.16) ^(a)  1 month 97.2 97.3 97.6 97.5 97.7 97.3 25° C.  3months 99.4 99.3 99.5 99.4 99.4 99.6 (0.22)^(a) (0.25)^(a) (0.30) ^(a)(0.04) ^(a)  6 months 99.1 98.9 99.4 99.2 99.2 99.6 (0.25)^(a) (0.27)(0.24) ^(a) (0.02) ^(a) 2-8° C.  3 months 99.8 99.7 99.9 99.7 99.7 99.7(0.11)^(a) (0.11) ^(a) (0.02) ^(a)  6 months 99.9 99.8 99.7 99.7 99.899.8 (0.06)^(a) (0.06)^(a) (0.09) 16 months 99.8 99.7 99.5 99.4 99.599.8 (0.46)^(a) (0.50)^(a) (0.42) ^(a) (0.04) ^(a) 24 months 99.7 n/a99.4 99.4 99.3 99.6 (0.50)^(a) (0.50)^(a) (0.54) ^(a) (0.25) ^(a) *Allformulations contain 0.01% polysorbate 20 ^(a) The values representedare high molecular species which elute ~12 minutes in the current SECHPLC method often referred to as the “12 minute peak. ” This peak isthought to be strongly associated with the presence of phosphate in theformulation.

SAX-HPLC

The data summary for SAX-HPLC is listed in Table 19. At thestressed/accelerated conditions, the saline formulations appeared hadslightly more changes (FIGS. 11 and 12) but at the long term storageconditions, there was no changes for all the formulations after 24months (Table 19 and FIG. 13). This indicates the saline formulationsare stable for 24 months at 2-8C.

TABLE 19 COMPARING CHANGES IN CHARGE BY SAX-HPLC METHOD FOR SALINE ANDPHOSPHATE FORMULATIONS (ALL WITH 0.01% POLYSORBATE-20) OVER 24 MONTHS100 50 mg/ml, mg/ml, 100 100 150 mM 150 mM mg/ml, 100 mg/ml, 50 mg/ml,mg/ml, NaCl, NaCl, 137 NaCl, 137 NaCl, 154 mM 154 mM 5 mM 5 mM 20 mM 20NaCl, NaCl, NaPO₄, NaPO₄, NaPO₄, mMNaPO₄, pH 6.0 pH 6.0 pH 6.5 pH 6.5 pH6.0 pH 6.5 Baseline A + B = 51; A + B = 51; A + B = 52; A + B = 50; A +B = 51; A + B = 52; E + F = 18 E + F = 18 E + F = 18 E + F = 18 E + F =17 E + F = 18 40° C.  2 weeks A + B = 51; A + B = 52; A + B = 51; A + B= 51; A + B = 51; A + B = 49; E + F = 16 E + F = 16 E + F = 17 E + F =17 E + F = 17 E + F = 17  1 month A + B = 50 A + B = 50; A + B = 50; A +B = 50; A + B = 50; A + B = 50; E + F = 17 E + F = 17 E + F = 17 E + F =17 E + F = 17 E + F = 17 25° C.  3 months A + B = 48; A + B = 48; A + B= 48; A + B = 47; A + B = 47; A + B = 47; E + F = 18 E + F = 18 E + F =18 E + F = 18 E + F = 18 E + F = 18  6 months A + B = 45; A + B = 45;A + B = 44; A + B = 45; A + B = 45; A + B = 44; E + F = 18 E + F = 18E + F = 18 E + F = 18 E + F = 18 E + F = 18 2-8° C.  3 months A + B =47; A + B = 47; A + B = 47; A + B = 47; A + B = 46; A + B = 47; E + F =18 E + F = 18 E + F = 18 E + F = 18 E + F = 18 E + F = 18  6 months A +B = 44; A + B = 44; A + B = 44; A + B = 44; A + B = 45; A + B = 44; E +F = 18 E + F = 19 E + F = 18 E + F = 18 E + F = 19 E + F = 19 16 monthsA + B = 51; A + B = 50; A + B = 51; A + B = 51; A + B = 49; A + B = 50;E + F = 18 E + F = 18 E + F = 19 E + F = 18 E + F = 19 E + F = 18 24months A + B = 52; A + B = 52; A + B = 52; A + B = 52; A + B = 52; A + B= 51; E + F = 18 E + F = 18 E + F = 18 E + F = 18 E + F = 17 E + F = 18

pH

Table 20 demonstrates that the pH of all the formulations remainedcomparable to the baseline for 24 months at 2-8° C. For the salineformulations, although there was no buffer, the pH maintained constantat 6.0 for 24 months.

TABLE 20 COMPARING PH FOR SALINE AND PHOSPHATE FORMULATIONS (ALL WITH0.01% POLYSORBATE-20) OVER 24 MONTHS AT 2-8° C. 50 100 50 100 mg/ml,mg/ml, 100 mg/ml, mg/ml, 150 mM 150 mM mg/ml, 100 mg/ml, 154 154 NaCl,NaCl, 137 NaCl, 137 NaCl, mM mM 5 mM 5 mM 20 mM 20 NaCl, NaCl, NaPO₄,NaPO₄, NaPO₄, mMNaPO₄, pH 6.0 pH 6.0 pH 6.5 pH 6.5 pH 6.0 pH 6.5Baseline 6.03 6.00 6.43 6.41 5.96 6.47 24 months 6.06 n/a 6.42 6.44 6.016.53

Enzyme Activity

Compared to the reference standard, the specific activity for all theformulations after 24 months at 2-8° C. was equivalent within the assayvariation, which suggest idursulfase remained stable in the salineformulation for 24 months (Table 21).

TABLE 21 ACTIVITY RESULTS BY ION EXCHANGE CHROMATOGRAPHY AFTER 24 MONTHSREAL TIME STABILITY (2-8° C.) IN SALINE AND PHOSPHATE FORMULATIONS 50100 50 100 mg/ml, mg/ml, 100 mg/ml, mg/ml, 150 mM 150 mM mg/ml, 100mg/ml, 154 154 NaCl, NaCl, 137 NaCl, 137 NaCl, mM mM 5 mM 5 mM 20 mM 20NaCl, NaCl, NaPO₄, NaPO₄, NaPO₄, mMNaPO₄, pH 6.0 pH 6.0 pH 6.5 pH 6.5 pH6.0 pH 6.5 Specific 43 n/a 42 51 49 45 Activity (U/mg) *The Specificactivity of the reference standard was 56 U/mg during testing 24 monthssamples.

Detection of Residual Phosphate Associated with the Protein

The final UF/DF step in preparing the saline formulation was used todiafilter the protein solution from 137 mM NaCl, 20 mM sodium phosphateinto 150 mM NaCl. To examine how the diafiltration cycle number affectsthe residual phosphate concentration in the final product, a lab scalestudy was conducted using the Drug Substance (2 mg/mL idursulfase, 137mM NaCl, 20 mM sodium phosphate, pH 6.0). The drug substance was firstconcentrated to 50 mg/mL idursulfase and then dialfiltered into 150 mMsaline. Samples were taken at 7×, 10×, and 15× diafiltration step andtested by ICP for phosphate content. The test results are summarized inTable 22. As shown, the saline diafiltration solution does not containany phosphate. After 7×DF, the protein contained about 0.22 mMphosphate, which was higher than theoretical calculated value. After10×DF, the protein retentate contained about 0.16 mM phosphate while theflow through was only about 0.07 mM phosphate, which indicated that thephosphate was binding to the protein. After 15×DF, the phosphate levelwas dropped to about 0.07 mM.

The results from the study indicated that about 0.2 mM phosphate residueremained in the Drug Substance, which likely contributed to maintainingthe pH of 6.0 for the saline formulation.

TABLE 22 SODIUM PHOSPHATE REMAINING WITH THE PROTEIN AFTER MULTIPLEDIAFILTRATION STEPS Sample ID μg/ml (ppm) mM Starting materialDP04-002-X N/A 20 150 mM NaCl solution (DF buffer) *below LOQ 0 ProteinRetentate after 7x DF 21 0.22 Protein Retentate after 10x DF 15 0.16Permeate (flow through) after 10X DF 7 0.07 Protein Retentate after 15xDF 7 0.07 DP06-004-X 21 0.22 *The starting saline buffer was tested andno detectable phosphate was detected.

Protein Concentration Effect on Maintaining Formulation pH

From the phosphate content analysis, apparently phosphate binds to theprotein. Therefore, it is expected high protein may bind more phosphate,which could maintain the pH better. To examine that hypothesis, theprotein in the saline solution was concentrated to different levels andpH of the solutions after different processing conditions was tested.The results are summarized in Table 23.

As shown, the initial pH of the solutions was maintained to about 6.0independent of the protein concentration. However, after ambientexposure for 24 hr or three freeze thaw cycles, the pH of the solutionscontaining 0.1 mg/mL protein or less did not maintain a constant pHaround 6.0. The pH of the solutions at the protein concentration ofabove 1 mg/mL was maintained around 6.0. This confirmed that the proteinconcentration is a controlling factor in maintaining the pH of thesaline solutions.

TABLE 23 EFFECT OF PROTEIN CONCENTRATION ON PH OF UNBUFFERED SALINEFORMULATIONS Protein pH after 24 hr pH After Three Concentration InitialAmbient Freeze Thaw (mg/mL) pH Exposure Cycles* 60 6.1 6.1 6.1 30 6.16.1 6.1 10 6.1 6.0 6.1 2 6.0 5.9 5.9 1 6.0 5.8 6.0 0.1 5.9 5.6 5.8 0.016.0 5.6 5.8 0 (saline) 6.1 5.7 5.6 *Samples were stored at ≤−65° C. forat least 1 hour and thawed at ambient temperature for 0.5 hour, and thiscycle was repeated three times.

The results from this study demonstrated that idursulfase in the salineformulation (50 mg/mL idursulfase, 0.005% polysorbate, 150 mM NaCl, pH6.0) is stable for at least 24 months when stored at 2-8C. Thisformulation appeared to be more stable compared to the phosphatecontaining formulation. The selection of 0.005% polysorbate 20 wassufficient to protect the protein against the shaking stress. Inaddition, the study also indicated that the pH of the saline formulationcan be stably maintained at 6.0 for 24 months at 2-8° C., in part due tothe residual phosphate and high protein concentration in the finalformulation.

Example 5. Biodistribution

Having successfully demonstrated that intrathecal administration is anefficacious way of delivering I2S to the tissues of the CNS, additionalstudies were conducted to determine whether IT-administered I2S iscapable of distributing into the deep tissues of the brain and whetherthere is cellular localization of IT-administered I2S. A recombinanthuman iduronate-2-sulfatase (I2S) formulation was prepared andformulated in a vehicle of 154 mM NaCl, 0.005% polysorbate 20 at a pH of6.0.

Non-human primates were administered either 3 mg, 30 mg, or 100 mg ofI2S on a monthly basis by way of an implanted intrathecal port for sixconsecutive months. The design of the study is summarized in Table 24below.

TABLE 24 Last Day on Study IV Dose (number of animals) Group n(mg/kg)^(a) IT Dose (mg)^(a) 6 Months Recovery 1 6 DC (NS) DC (PBS) 6 —2 12 0 (vehicle) 0 (IT vehicle) 6 6 3 12 0.5 3 6 6 4 6 0.5 30 6 — 5 120.5 100 6 6 ^(a)Idursulfase unless otherwise specified. DC (devicecontrol); IT (intrathecal); IV (intravenous); NS (normal saline); PBS(phosphate-buffered saline, pH 7.2).

Repeat monthly administration of I2S to the non-human primates for sixmonths was well tolerated at the highest dose tested and not associatedwith any significant adverse toxicologic events. Twenty-four hoursfollowing the administration of the sixth and final dose of I2S, thesubject non-human primates were sacrificed and CNS tissues of suchnon-human primates were examined.

As determined by immunohistochemistry (IHC), there was widespreadcellular deposition of I2S throughout the cells and tissues of the CNS.I2S protein was detected in all tissues of the brain by IHC, with adeposition gradient from the cerebral cortex to the ventricular whitematter. In the gray matter I2S was detected in the neurons of thecerebrum, cerebellum, brain stem, and spinal cord of all groups in adose-dependent manner. In the surface gray matter of the higher dosegroups, large numbers of cerebral neurons were positive for I2S stainingin the surface cortex (FIG. 40A). I2S was also detected in neurons inthe thalamus (FIG. 40B), hippocampus (FIG. 40C), caudate nucleus FIG.40D) and spinal cord (FIG. 40E). Meningial and perivascular cells werealso positive for I2S staining (FIG. 40F).

As depicted in FIGS. 41 and 42, distribution of IT-administered I2S intothe tissues of the CNS and in particular deposition in the gray matter,thalamus and cerebral cortex of the subject non-human primates isevident. Furthermore, FIGS. 42 and 43 illustrate that theIT-administered I2S accumulates in the depicted CNS tissues of thesubject non-human primates in a dose dependant manner. Co-localizationstaining also revealed that IT administration of I2S associates withboth neurons and oligodendrocytes. The IT-administered I2S alsodistributes and localizes throughout the cerebrum of the subjectnon-human primates as evidenced by FIG. 44. In particular, FIG. 45illustrates neuronal uptake and axonal association of the I2S followingIT-administration to the non-human primates, as demonstrated by filamentstaining. Also of particular interest, the present studies illustratethat I2S is selective for neuronal cells and such neuronal cellsfacilitate the distribution of intrathecally-administered I2S into thedeep tissues of the brain and appears to be associated with axonalstructures, indicating anterograde axonal transport of I2S.

Table 25 below present the pharmacokinetic data of variousadministration routes and doses for a separate animal study.

TABLE 25 Body Brain Dose Dose AUClast weight weight mg/kg mg/kg unithr*ng/mL kg kg BW Br wt 0.5 8331 2.7 0.1 0.5 5 mg/kg 1 mg, IT 1933 3.10.1 0.32 10 10 mg, 31316 2.7 0.1 3.66 100 IT 30 mg, 140345 2.9 0.1 10.34300 IT

¹²⁴I-labeled I2S was administered to test animals as shown in Table 26below and PET scan results are shown in FIG. 62, FIG. 63.

TABLE 26 Animals/ Group Group Route Test Article Dose 1 1 ICV [124I]- 3mg idursulfase 2 4 IT-L [124I]- 3 mg idursulfase 3 4 IV [124I]- 0.1mg/kg idursulfase 4 4 IV [124I]- 1 mg/kg idursulfase

The present studies also demonstrated the cellular identification ofIT-administered I2S in white matter brain tissue near the ventricles ofthe subject non-human primates following IT-administration. While theI2S staining density in the white matter was generally lower than thegray matter, I2S was detected within oligodendrocytes (FIG. 46). Inparticular, FIG. 46 illustrates the cellular identification of I2S inwhite matter brain tissues and further demonstrates that I2S does notappear to associate with myelin.

In addition to demonstrating the distribution of IT-administered I2Sdeep into the tissues of the brain, the present studies also confirmedlocalization of I2S into the target organelles, and importantlylocalization of I2S into the lysosomes which are affected organelles inthe lysosomal storage disorders, such as Hunter's syndrome. Inparticular, I2S was located within the lysosomes and also detectedwithin axons. FIG. 46 illustrates the localization of IT-administeredI2S within the lysosomes of oligodendrocytes of the subject non-humanprimate, thereby confirming that IT-administered I2S is capable ofdistributing into the deep tissues of the brain and is capable ofcellular localization.

In order to discern whether the delivered I2S retained biologicalactivity, levels of I2S in the brain were measured utilizing a specificactivity assay. The activity in the brain of the 3 mg IT group 24 hoursafter the last dose was not apparently different from the basal levelsin the device control and vehicle control animals. Enzyme activity inthe brain of 30 mg and 100 mg IT dosed animals was above baseline atnecropsy (24 hours post-dose).

Further animal tests to discern the biodistribution of I2S following ITdelivery to the brain is shown in FIG. 60 and the sample numberscorrespond to Table 27 below.

TABLE 7 LOCATION OF SAMPLES Sample Number Structure 1 Cerebral cortex-superficial (L) 2 Cerebral cortex- superficial (R) 3 Caudate nucleus (R)4 Caudate nucleus (L) 5 Corpus callosum 6 Cerebral cortex(frontal)-superficial (L) 7 Cerebral cortex(frontal)- superficial (R) 8 Whitematter- superficial (L) 9 White matter- superficial (R) 10 Whitematter-deep (L) 11 White matter-deep (R) 12 Cerebal cortex(temporal)-superficial (L) 13 Cerebal cortex (temporal)-superficial (R)14 Thalamus (L) 15 Thalamus (R) 16 Hypothalamus (L) 17 Hypothalamus (R)18 Hippocampus (L) 19 Hippocampus (R) 20 White matter-deep (L) 21 Whitematter-superficial (R) 22 Corpus callosum 23 White matter-deep (L) 24White matter-deep (R) 25 Cerebellum (R)

Example 6. IT Vs. ICV Delivery

The I2S distribution patterns observed in the foregoing example was alsorecapitulated in healthy Beagle dogs given a single IT or ICV dose. MaleBeagle dogs were randomized using computer-generated numbers into twogroups (Group 1 (ICV), N=3; Group 2 (IT); N=4). All had cathetersimplanted in the subarachnoid space at the lumbar spine or in the leftlateral cerebral ventricle (for dosing) and in the cisterna magna (forsampling). All catheters terminated in a subcutaneous titanium accessport. An additional dog was used as an un-dosed surgical control.

A single bolus 1 ml injection of I2S (30 mg/ml in 20 mM sodiumphosphate, pH 6.0; 137 mM sodium chloride; 0.02% polysorbate-20), wasadministered IT or ICV, followed by a 0.3 ml flush with phosphatebuffered saline (PBS; pH 7.2). Clinical signs were monitored andsacrifice occurred 24 hours following the dose. Brain and spinal cordtissue samples were collected for quantitative I2S analyses asdetermined by ELISA, I2S enzyme activity and IHC, and compared betweenthe study groups.

I2S was widely distributed throughout the gray matter of both IT and ICVgroups as determined by IHC. In the cerebral cortex, neurons werepositive for I2S in all six neuronal layers, from the surface molecularlayer to the deep internal layer in both IT and ICV groups, asillustrated by Figure. 47 (A and B). In the cerebellar cortex of the ITand ICV groups, I2S was detected in neurons, including Purkinje cells,as illustrated by FIG. 47 (C and D). In both IT and ICV groups a largepopulation of neurons in the hippocampus was positive for I2S, asdemonstrated by FIG. 47 (E and F). I2S positive neurons were also foundin the thalamus and caudate nucleus in both of the groups, asillustrated in FIG. 47 (G and H).

The present studies therefore confirm the ability of IT-administeredenzymes to distribute into the deep cells and tissues of the brain andsupport the utility of IT-administered enzymes such as I2S for thetreatment of the CNS manifestations associated with lysosomal storagediseases, such as Hunter's syndrome.

Example 7: Iduronate-2-Sulfatase Deficient Mouse Model

Having demonstrated that IT-administered I2S is capable of distributinginto the deep tissues of the brain and cellular localization of I2S,further studies were conducted to determine the therapeutic efficacy ofIT-administered I2S. A genetically-engineered iduronate-2-sulfataseknock-out (IKO) mouse model of Hunter syndrome was developed to studythe ability of the IT-administered I2S to alter disease progression. TheI2S knock-out mouse model was developed using a targeted disruption ofthe I2S locus which results in an accumulation of glycosaminoglycans(GAG) in tissues and organs. The IKO mouse model exhibits many of thephysical characteristics of Hunter syndrome seen in humans, includingthe characteristic coarse features and skeletal defects. In addition,the IKO mouse model demonstrates elevated glycosaminoglycan (GAG) levelsin urine and in tissues throughout the body, as well as widespreadcellular vacuolization which was observed hi stopathologically.

In the present study, commercially-available I2S (Elaprase®) wasconcentrated and re-suspended in phosphate buffered saline (PBS). Sixgroups of male IKO mice, 8-12 weeks old, were treated with I2S (10μ1; 26mg/ml). Groups A and B (N=3) were intrathecally administered three 260μg doses (at days 1, 8, and 15) and two 260 μg doses (at days 1 and 8)of I2S, respectively. Group D was also treated with three intrathecallyadministered 260 μg doses at days 1, 8, and 15. Group C and E (N=3) wereuntreated control groups and group F (N=3) was an untreated wild-typecontrol. Control mice were administered a vehicle without I2S. Mice weresacrificed after 1 hour following the last injection, followed by tissuepreparation for immunohistochemistry (IHC) and histopathologicalanalysis.

Following the third injection, there was widespread reduction ofcellular vacuolation in the surface cerebral cortex, caudate nucleus,thalamus and the cerebellum in I2S-treated mice compared tovehicle-treated mice. Reductions in cellular vacuolation were also foundin the white matter after IT treatment. Distribution of I2S to the braintissues of the IKO mouse was evident following IT-administration.

Three weekly IT administrations of I2S in the IKO mice also demonstrateda marked reduction in CNS cellular vacuolization at both light andelectronic microscopic levels. Following IT administration of I2S, areduction of cellular vacuolation was evident relative to untreated IKOmice, suggesting that IT-administered I2S is capable of altering diseaseprogression. As illustrated in FIG. 48, a reduction of cellularvacuolation was evident in the corpous callosum and fornix of the IKOmice following IT-administration of I2S. FIG. 49 illustrates a markedreduction in the presence of lysosomal associated membrane protein 1(LAMP1), a lysosomal disease pathological biomarker, in the surfacecerebral cortex tissues of the treated IKO mouse.

Additionally, electron microscopy demonstrated a reduction in thepresence of storage inclusions in neurons in the gray matter andvacuolation in oligodendrocytes in the white matter. In particular, theIKO mice IT-administered 12S also demonstrated a reduction in palisadedlamellar bodies (“zebra bodies”) which are characteristic of certainlysosomal storage diseases. In particular, FIG. 5 represents an electronmicroscope scan illustrating a reduction of the characteristic zebrabodies in the neurons of the IKO mouse that was administered I2S,relative to the untreated IKO mouse. Similarly, FIG. 5 illustrates anelectron microscope scan of oligodendrocytes in the corpus callosum.

In addition, the IT administrations of I2S to the IKO mice alsodemonstrated a marked reduction in the lysosomal disease pathologicalbiomarker lysosomal associated membrane protein 1 (LAMP1)immunostaining, an indicator of lysosomal activity and disease state, inthe surface cerebral cortex, caudate nucleus, thalamus, cerebellum andwhite matter. As illustrated in FIG. 49A, a marked reduction in LAMP1immunostaining is evident in the treated IKO mouse surface cerebralcortex tissue relative to the untreated IKO control mouse surfacecerebral cortex tissue illustrated in FIG. 49B, reflecting animprovement in disease pathology.

FIG. 20 quantitatively illustrates and compares the concentration ofLAMP1 measured in μm² areas of brain tissue. Morphometrical analysis ofLAMP-1 immunostaining of various brain regions confirmed that there weresignificant reductions in the LAMP-1 positive staining in all areas ofthe brain evaluated. As shown in FIG. 4, in each area of brain tissueevaluated (the cortex, caudate nucleus and putamen (CP), thalamus (TH),cerebellum (CBL) and white matter (WM)) the LAMP-positive area wasreduced in the treated IKO mice relative to the untreated IKO controlmice, and approached the LAMP-positive area of the wild-type mice.Particularly notable is that the LAMP-positive areas in each area ofbrain tissue analyzed were further reduced with continued treatmentduration.

Reduction of abnormally high lysosomal activity correlated with dramaticmorphological improvements in all areas of the brain. These resultsconfirm that IT-administered I2S is capable of altering progression oflysosomal storage diseases, in a genetically-engineered IKO mouse model,further confirming the ability of IT-administered enzymes such as I2S totreat the CNS manifestations associated with lysosomal storage diseases,such as Hunter's syndrome.

Example 8: Treatment of Hunter's Disease Patients

Direct CNS administration through, e.g., IT delivery can be used toeffectively treat Hunter's Disease patients. This example illustrates amulticenter dose escalation study designed to evaluate the safety of upto 3 dose levels every other week (EOW) for a total of 40 weeks of I2Sadministered via an intrathecal drug delivery device (IDDD) to patientswith late infantile Hunter's Disease. Various exemplary intrathecal drugdelivery devices suitable for human treatment are depicted in FIGS.45-48.

Up to 20 patients will be enrolled:

Cohort 1: 5 patients (Lowest Dose)

Cohort 2: 5 patients (Intermediate Dose)

Cohort 3: 5 patients (Highest Dose)

5 patients will be randomized to no treatment.

Patients are selected for the study based on inclusion of the followingcriteria: (1) appearance of first symptoms prior to 30 months of age;(2) ambulatory at the time of screening (defined as the ability to standup alone and walk forward 10 steps with one hand held); (3) presence ofneurological signs at time of screening. Typically, patients having ahistory of hematopoietic stem cell transplantation are excluded.

Safety of ascending doses of I2S administered by IT injection for 40weeks in children with late infantile Hunter's Disease is determined. Inaddition, the clinical activity of I2S on gross motor function, andsingle and repeated-dose pharmacokinetics in serum and concentrations incerebrospinal fluid (CSF) are assessed.

A therapeutically effective amount of I2S is administered intrathecallyat regular intervals, depending on the nature and extent of thedisease's effects, and on an ongoing basis. Administration at an“interval,” as used herein, indicates that the therapeutically effectiveamount is administered periodically (as distinguished from a one-timedose). The interval can be determined by standard clinical techniques.In some embodiments, I2S is administered intrathecally approximatelyevery other week. The administration interval for a single individualneed not be a fixed interval, but can be varied over time, depending onthe needs of the individual. For example, in times of physical illnessor stress, if anti-12S antibodies become present or increase, or ifdisease symptoms worsen, the interval between doses can be decreased.

Example 9—Treatment of Hunter's Disease Patients

Direct CNS administration through, e.g., IT delivery can be used toeffectively treat Hunter's Disease patients. This example illustrates amulticenter dose escalation study designed to evaluate the safety of upto 3 dose levels everymonth for a total of 6 months of I2S administeredvia an intrathecal drug delivery device (IDDD) to patients with lateinfantile Hunter's Disease. Various exemplary intrathecal drug deliverydevices suitable for human treatment are depicted in FIGS. 45-48 and aschematic of the trial is shown in FIG. 62.

Up to 16 patients will be enrolled:

Cohort 1: 4 patients (Lowest Dose—10 mg)

Cohort 2: 4 patients (Intermediate Dose—30 mg)

Cohort 3: 4 patients (Highest Dose—100 mg)

4 patients will be randomized to no treatment or use of device.

Hunter's Disease patients frequently develop cognitive andneurodevelopmental impairment including delay of early developmentmilestones (e.g., walking, speech, toilet training), intellectualdeficit, hyperactivity, aggression, hearing impairment, epilepsy andhydrocephalus. All of the indications can be part of the criteria fortrials. Patients are selected for the study based on inclusion of thefollowing criteria: (1) 3-18 years of age; (2) intelligence quotient ofless than 77 or a decline of 15 to 30 IQ points in past 3 years; (3) noCSF shut or poorly controlled seizure disorder and (4) no co-morbiditiespresenting anesthesia and/or surgical risks.

Safety of ascending doses of I2S administered by IT injection for 6months in children with late infantile Hunter's Disease is determined.In addition, the clinical activity of I2S on gross motor function, andsingle and repeated-dose pharmacokinetics in serum and concentrations incerebrospinal fluid (CSF) are assessed.

Objectives of the study will be to evaluate the safety and tolerabilityof ascending doses of I2S, as well as the safety, tolerability and longterm patency of the IDDD. Additionally, the concentration of I2S aftersingle and repeated IT doses in both CSF and peripheral blood, as wellas the effects of 12S on CF biomarkers and urinary GAG will be assessed.Further evaluation will include effects of I2S on clinical parameterssuch as physiological and neurocognitive assessments, neuro-function andbrain structure volumes. Additionally, the effects of treatment on dailyliving and relationships between biomarkers and symptoms can beevaluated.

Treatment of Hunter's Disease patients by IT delivery of 128 results inreduction of accumulation of sulfatide in various tissues (e.g., thenervous system, heart, liver, kidneys, gallbladder, and other organs).

While certain compounds, compositions and methods described herein havebeen described with specificity in accordance with certain embodiments,the following examples serve only to illustrate the compounds of theinvention and are not intended to limit the same.

The articles “a” and “an” as used herein in the specification and in theclaims, unless clearly indicated to the contrary, should be understoodto include the plural referents. Claims or descriptions that include“or” between one or more members of a group are considered satisfied ifone, more than one, or all of the group members are present in, employedin, or otherwise relevant to a given product or process unless indicatedto the contrary or otherwise evident from the context. The inventionincludes embodiments in which exactly one member of the group is presentin, employed in, or otherwise relevant to a given product or process.The invention also includes embodiments in which more than one, or theentire group members are present in, employed in, or otherwise relevantto a given product or process. Furthermore, it is to be understood thatthe invention encompasses all variations, combinations, and permutationsin which one or more limitations, elements, clauses, descriptive terms,etc., from one or more of the listed claims is introduced into anotherclaim dependent on the same base claim (or, as relevant, any otherclaim) unless otherwise indicated or unless it would be evident to oneof ordinary skill in the art that a contradiction or inconsistency wouldarise. Where elements are presented as lists, (e.g., in Markush group orsimilar format) it is to be understood that each subgroup of theelements is also disclosed, and any element(s) can be removed from thegroup. It should be understood that, in general, where the invention, oraspects of the invention, is/are referred to as comprising particularelements, features, etc., certain embodiments of the invention oraspects of the invention consist, or consist essentially of, suchelements, features, etc. For purposes of simplicity those embodimentshave not in every case been specifically set forth in so many wordsherein. It should also be understood that any embodiment or aspect ofthe invention can be explicitly excluded from the claims, regardless ofwhether the specific exclusion is recited in the specification. Thepublications, websites and other reference materials referenced hereinto describe the background of the invention and to provide additionaldetail regarding its practice are hereby incorporated by reference.

1-61. (canceled)
 62. A method of treating Hunter Syndrome comprising astep of administering intraventricularly (ICV) to a human subject inneed of treatment a formulation comprising an iduronate-2-sulfatase(I2S) protein at a concentration of at least 5 mg/ml and no greater than50 mM phosphate.
 63. The method of claim 62, wherein the formulationcontains a phosphate concentration no greater than 20 mM.
 64. The methodof claim 63, wherein the formulation comprises phosphate at aconcentration of no greater than 5 mM.
 65. The method of claim 62,wherein the I2S protein is present at a concentration of at least about10 mg/ml.
 66. The method of claim 62, wherein the I2S protein is presentat a concentration of approximately 30 mg/ml.
 67. The method of claim62, wherein the I2S protein comprises an amino acid sequence of SEQ IDNO:1.
 68. The method of claim 62, wherein the formulation furthercomprises salt.
 69. The method of claim 68, wherein the salt is NaCl.70. The method of claim 62, wherein the formulation further comprisespolysorbate.
 71. The method of claim 70, wherein the polysorbate ispolysorbate 20 present at a concentration of approximately 0.005-0.02%.72. The method of claim 62, wherein the formulation has a pH ofapproximately 5.5-6.5.
 73. The method of claim 62, wherein theformulation is a liquid formulation.
 74. The method of claim 62, whereinthe formulation is formulated as lyophilized dry powder.
 75. The methodof claim 62, wherein the formulation further comprises NaCl at aconcentration of approximately 154 mM, polysorbate 20 at a concentrationof approximately 0.005%, and a pH of approximately
 6. 76. The method ofclaim 62, wherein the I2S protein is a synthetic, recombinant,gene-activated or natural enzyme.
 77. The method of claim 62, whereinthe formulation is administered in a volume of about 1-15 ml.
 78. Themethod of claim 62, wherein the formulation is administered at a dose ofat least 10 mg.
 79. A method of treating Hunter Syndrome, comprising astep of administering intraventricularly (ICV) to a human subject inneed of treatment a formulation comprising an iduronate-2-sulfatase(I2S) protein at a concentration at or greater than 5 mg/ml, salt at aconcentration of approximately 154 mM, a polysorbate surfactant at aconcentration of approximately 0-0.02%, and a pH of approximately5.5-6.5; wherein the formulation is administered at a volume of about1-5 ml.
 80. A pharmaceutical composition for intraventricularadministration comprising an iduronate-2-sulfatase (I2S) protein at aconcentration of at least 5 mg/ml and no greater than 50 mM phosphate.81. A container comprising a single dosage form of the pharmaceuticalcomposition of claim 80.